Practice Test

Q1) A constant volume gas thermometer works on Show Answer

Q2) The wire used in resistance thermometer is platinum wire because Show Answer

Q3) What is 273.00 K on the Celsius scale of temperature? Show Answer

Q4) Which of the following temperatures is the highest? Show Answer

Q5) By what factor, the volume of the metal submerged in mercury changes. Show Answer

Q6) Mercury thermometer can be used to measure temperature up to Show Answer

Q7) One fixed point of temperature used in the absolute scale is Show Answer

Q8) Two spheres of same size are made of the same metal but one is hollow and the other is solid. They are heated to same temperature. Then Show Answer

Q9) The ratio of the densities of the two bodies is 3 : 4 the ratio of specific heats is 4 : 3. The ratio of their thermal capacities for unit volume is Show Answer

Q10) Recently, the phenomenon of super conductivity has been observed at 95 K. This temperature is nearly equal to Show Answer

Q11) Statement 1: The ratio of specific heat capacity to molar heat capacity of a gas depends on the molecular mass of the gas.
Statement 2: One mole of the gas contains its molecular mass in grams. Show Answer

Q12) The ratio of melting points of P to Q is : Show Answer

Q13) The ratio of latent heats of fusion of P to Q is : Show Answer

Q14) The ratio of specific heat of P to Q in solid state is : Show Answer

Q15) Thermoelectric thermometer is based on Show Answer

Q16) The study of physical phenomenon at low temperatures (below liquid nitrogen temperature) is called Show Answer

Q17) ‘Stem Correction’ in platinum resistance thermometers are eliminated by the use of Show Answer

Q18) The absolute zero is the temperature at which Show Answer

Q19) Absolute scale of temperature is reproduced in the laboratory by making use of a Show Answer

Q20) On which of the following scales of temperature, the temperature is never negative Show Answer

Q21) One quality of a thermometer is that its heat capacity should be small. If P is a mercury thermometer, Q is a resistance thermometer and R thermocouple type then Show Answer

Q22) Two thermometers are used to record the temperature of a room. If the bulb of one is wrapped in wet hanky Show Answer

Q23) At what temperature the centigrade (Celsius) and Fahrenheit, readings are the same Show Answer

Q24) Standardisation of thermometers is obtained with Show Answer

Q25) The gas thermometers are more sensitive than liquid thermometers because Show Answer

Q26) Mercury thermometers can be used to measure temperatures upto Show Answer

Q27) A device used to measure very high temperature is Show Answer

Q28) The absolute zero temperature in Fahrenheit scale is Show Answer

Q29) A constant pressure air thermometer gave a reading of 47.5 units of volume when immersed in ice cold water, and 67 units in a boiling liquids. The boiling point of the liquid will be Show Answer

Q30) Of the following thermometers, the one which can be used for measuring a rapidly changing temperature is a Show Answer

Q31) On centigrade scale the temperature of a body increases by 30 degrees. The increase in temperature on Fahrenheit scale is Show Answer

Q32) The apparent coefficient of expansion of a liquid when heated in a copper vessel is C and when heated in a silver vessel is S. If A is the linear coefficient of expansion of copper, then the linear coefficient of expansion of silver is Show Answer

Q33) When a rod is heated but prevented from expanding, the stress developed is independent of Show Answer

Q34) Expansion during heating Show Answer

Q35) A solid ball of metal has a concentric spherical cavity within it. If the ball is heated, the volume of the cavity will Show Answer

Q36) A litre of alcohol weighs Show Answer

Q37) 5 litre of benzene weighs Show Answer

Q38) Water has maximum density at Show Answer

Q39) At some temperature T, a bronze pin is a little large to fit into a hole drilled in a steel block. The change in temperature required for an exact fit is minimum when Show Answer

Q40) If the length of a cylinder on heating increases by 2%, the area of its base will increase by Show Answer

Q41) In cold countries, water pipes sometimes burst, because Show Answer

Q42) A brass disc fits simply in a hole of a steel plate. The disc from the hole can be loosened if the system Show Answer

Q43) When vapour condenses into liquid Show Answer

Q44) If specific heat of a substance is infinite, it means Show Answer

Q45) A quantity of heat required to change the unit mass of a solid substance, from solid state to liquid state, while the temperature remains constant, is known as Show Answer

Q46) The latent heat of vaporization of a substance is always Show Answer

Q47) The factor not needed to calculate heat lost or gained when there is no change of state is Show Answer

Q48) Water is used to cool radiators of engines, because Show Answer

Q49) Melting point of ice Show Answer

Q50) Two spheres made of same substance have diameters in the ratio 1 : 2. Their thermal capacities are in the ratio of Show Answer

Q51) If mass energy equivalence is taken into account, when water is cooled to form ice, the mass of water should Show Answer

Q52) Amount of heat required to raise the temperature of a body through 1K is called its Show Answer

Q53) A liquid of mass m and specific heat c is heated to a temperature 2T. Another liquid of mass m/2 and specific heat 2c is heated to a temperature T. If these two liquids are mixed, the resulting temperature of the mixture is Show Answer

Q54) By exerting a certain amount of pressure on an ice block, you Show Answer

Q55) A water fall is 84 metres high. If half of the potential energy of the falling water gets converted to heat, the rise in temperature of water will be Show Answer

Q56) A body of mass 5 kg falls from a height of 30 metre. If its all mechanical energy is changed into heat, then heat produced will be Show Answer

Q57) In supplying 400 calories of heat to a system, the work done will be Show Answer

Q58) 0.93 watt-hour of energy is supplied to a block of ice weighing 10 gm. It is found that Show Answer

Q59) The temperature of Bhakhra dam water at the ground level with respect to the temperature at high level should be Show Answer

Q60) Of two masses of 5 kg each falling from height of 10 m, by which 2kg water is stirred. The rise in temperature of water will be Show Answer

Q61) A lead ball moving with a velocity V strikes a wall and stops. If 50% of its energy is converted into heat, then what will be the increase in temperature (Specific heat of lead is S) Show Answer

Q62) The mechanical equivalent of heat J is Show Answer

Q63) Water falls from a height of 210m. Assuming whole of energy due to fall is converted into heat the rise in temperature of water would be (J = 4.3 Joule/cal) Show Answer

Q64) A block of mass 100 gm slides on a rough horizontal surface. If the speed of the block decreases from 10 m/s to 5 m/s, the thermal energy developed in the process is Show Answer

Q65) 4200 J of work is required for Show Answer

Q66) In a water-fall the water falls from a height of 100 m. If the entire K.E. of water is converted into heat, the rise in temperature of water will be Show Answer

Q67) A lead bullet of 10 g travelling at 300 m/s strikes against a block of wood and comes to rest. Assuming 50% of heat is absorbed by the bullet, the increase in its temperature is
(Specific heat of lead = 150J/kg, K) Show Answer

Q68) The temperature at which the vapour pressure of a liquid becomes equals to the external (atmospheric) pressure is its Show Answer

Q69) Calorimeters are made of which of the following Show Answer

Q70) A liquid boils when its vapour pressure equals Show Answer

Q71) During constant temperature, we feel colder on a day when the relative humidity will be Show Answer

Q72) Which of the following is the unit of specific heat Show Answer

Q73) The freezing point of the liquid decreases when pressure is increased, if the liquid Show Answer

Q74) Which of the following has maximum specific heat Show Answer

Q75) The point on the pressure temperature phase diagram where all the phases co-exist is called Show Answer

Q76) Boiling water is changing into steam. At this stage the specific heat of water is Show Answer

Q77) The thermal capacity of a body is 80 cal, then its water equivalent is Show Answer

Q78) A liquid of mass M and specific heat S is at a temperature 2t. If another liquid of thermal capacity 1.5 times, at a temperature of t/3 is added to it, the resultant temperature will be Show Answer

Q79) Dry ice is Show Answer

Q80) Two metal strips that constitute a thermostat must necessarily differ in their Show Answer

Q81) If a liquid is heated in weightlessness, the heat is transmitted through Show Answer

Q82) If black wire of platinum is heated, then its colour first appear red, then yellow and finally white. It can be understood on the basis of Show Answer

Q83) Let there be four articles having colours blue, red, black and white. When they are heated together and allowed to cool, which article cool at the earliest Show Answer

Q84) Woolen clothes are used in winter season because woolen clothes Show Answer

Q85) Which of the following statements is true/correct Show Answer

Q86) For a perfectly black body, its absorptive power is Show Answer

Q87) The cause of Fraunhoffer lines is Show Answer

Q88) The quantity of heat which crosses per unit area of a metal plate during conduction depends upon Show Answer

Q89) The luminosity of the Rigel star is 17000 times that of the sun. Assume both to be perfectly black bodies. If the surface temperature of the sun is 6000 K, then the temperature of the star is Show Answer

Q90) A metal sphere of radius r and specific heat c is rotated about an axis passing through its centre at a speed of n rotations per second. It is suddenly stopped and 50% of its energy is used in increasing its temperature. Then the rise in temperature of the sphere is Show Answer

Q91) The spectrum from a black body radiation is a Show Answer

Q92) The amount of radiation emitted by a perfectly black body is proportional to Show Answer

Q93) One gram of ice is mixed with one gram of steam. At thermal equilibrium the temperature of mixture is Show Answer

Q94) Which one of the following processes depends on gravity? Show Answer

Q95) Four pieces of iron heated in a furnace to different temperatures show different colours listed below. Which one has the highest temperature Show Answer

Q96) Boiling water is changing into steam. At this stage then specific heat of water is Show Answer

Q97) An ideal black body at room temperature is thrown into a furnance. It is observed that Show Answer

Q98) Two beakers A and B are filled to the brim with water at 4℃. When A is heated and B is cooled, the water Show Answer

Q99) The sprinkling of water reduces slightly the temperature of a closed room because Show Answer

Q100) In MKS system, Stefan’s constant is denoted by σ. In CGS system multiplying factor of σ will be Show Answer

Q101) A gas in an airtight container is heated from 25℃ to 90℃. The density of the gas will Show Answer

Q102) Work done in converting one gram of ice at -10℃ into steam at 100℃ is Show Answer

Q103) A sphere, a cube and a thin circular plate, all made of the same material and having the same mass are initially heated to a temperature of 1000℃. Which one of these will cool first Show Answer

Q104) If the temperature of a hot body is increased by 50% then the increase in the quantity of emitted heat radiation will be Show Answer

Q105) Heat capacity of a substance is infinite. It means Show Answer

Q106) It is known that wax contracts on solidification. If molten wax is taken in a large vessel and it is allowed to cool slowly, then Show Answer

Q107) At a common temperature, a block of wood and a block of metal feel equally cold or hot. The temperature of block of wood and block of metal are Show Answer

Q108) A faulty thermometer has its fixed points marked 5 and 95. When this thermometer reads 68, the correct temperature in Celsius is Show Answer

Q109) Newton’s law of cooling is used in laboratory for the determination of the Show Answer

Q110) A hollow copper sphere S and a hollow copper cube C, both of negligible thin walls of same area, are filled with water at 90℃ and allowed to cool in the same environment. The graph that correctly represents their cooling is Show Answer

Q111) In a pressure cooker, cooking is faster because the increase of vapour pressure Show Answer

Q112) A gas undergoes an adiabatic change. Its specific heat in the process is Show Answer

Q113) 1 g of a steam at 100℃ melts how much ice at 0℃? (Latent heat of ice =80 cal/gm and latent heat of steam =540 cal/gm ) Show Answer

Q114) The temperature, at which Centigrade and Fahrenheit scales give the same reading is Show Answer

Q115) There are two spherical balls A and B of the same material with same surface, but the diameter of A is half that of B. If A and B are heated to the same temperature and then allowed to cool, then Show Answer

Q116) The maximum energy in thermal radiation from a source occurs at the wavelength 4000Å. The effective temperature of the source is Show Answer

Q117) The temperature at which a black body of unit area loses its energy at the rate of 1 joule/second is Show Answer

Q118) An experiment takes 10 min to raise temperature of water from 0℃ and 100℃ and another 55 min to convert it totally into steam by a stabilized heater. The latent heat of vaporization comes out to be Show Answer

Q119) A calorimeter of mass 0.2 kg and specific heat 900 J/kg-K. Containing 0.5 kg of a liquid of specific heat 2400 J/kg-K. Its temperature falls from 60℃ to 55℃ in one minute. The rate of cooling is Show Answer

Q120) A partition wall has two layers A and B in contanct, each made of a different material. They have the same thickness but the thermal conductivity of layer A is twice that of layer B. If the steady state temperature difference across the wall is 60K, then the corresponding difference across the layer A is Show Answer

Q121) A block of mass 100 gm slides on a rough horizontal surface. If the speed of the block decreases from 10 m/s to 5 m/s, the thermal energy developed in the process is Show Answer

Q122) Three very large plates of same area are kept parallel and close to each other. They are considered as ideal black surfaces and have very high thermal conductivity. The first and third plates are maintained at temperatures 2T and 3T respectively. The temperature of the middle (i.e. second) plate under steady state condition is Show Answer

Q123) Water falls from a height of 500 m. What is the rise in temperature of water at the bottom if whole energy is used up in heating water? Show Answer

Q124) If a black body is heated at a high temperature, it seems to be Show Answer

Q125) The lengths and radii of two rods made of same material are in the ratios 1:2 and 2:3 respectively. If the temperature difference between the ends for the two rods be the same, then in the steady state, the amount of heat flowing per second through them will be in the ratio Show Answer

Q126) Triple point of water is Show Answer

Q127) Which of the following statements is wrong Show Answer

Q128) If l is length A is the area of cross section and K is thermal conductivity, then the thermal resistance of the block is given by Show Answer

Q129) Which of the following is the example of ideal black body Show Answer

Q130) A block of metal is heated to a temperature much higher than the room temperature and allowed to cool in a room free from air currents. Which of the following curves correctly represents the rate of cooling Show Answer

Q131) The heat is flowing through two cylindrical rods of same material. The diameters of the rods are in the ratio 1:2 and their lengths are in the ratio 2:1. If the temperature difference between their ends is the same, the ratio of rate of flow of heat through them will be Show Answer

Q132) A metallic ball and highly stretched spring are made of the same material and have the same mass. They are heated so that they melt, the latent heat required Show Answer

Q133) The temperature of equal masses of three different liquids A, B and C are 12℃, 19℃ and 28℃ respectively. The temperature when A and B are mixed is 16℃ and when B and C are mixed is 23℃. The temperature when A and C are mixed is Show Answer

Q134) Two spheres made of same material have radii in the ratio 2:1. If both the spheres are at same temperature, then what is the ration of heat radiation energy emitted per second by them? Show Answer

Q135) The original temperature of a black body is 727℃. The temperature at which this black body must be raised so as to double the total radiant energy, is Show Answer

Q136) Latent heat of 1gm of steam is 536 cal/gm, then its value in joule/kg is Show Answer

Q137) Two rectangular blocks A and B of different metals have same length and same area of cross-section. They are kept in such a way that their cross-sectional area touch each other. The temperature at one end of A is 100℃ and that of B at the other end is 0℃. If the ratio of their thermal conductivity is 1 : 3, then under steady state, the temperature of the junction in contact will be Show Answer

Q138) The volume of a metal sphere increases by 0.24% when its temperature is raised by 40℃ . The coefficient of linear expansion of the metal is …/℃. Show Answer

Q139) Flash light equipped with a new set of batteries, produces bright white light. As the batteries were out Show Answer

Q140) For proper ventilation of building, windows must be open near the bottom and top of the walls so as to let pass Show Answer

Q141) Two thermometers A and B are exposed in sun light. The valve of A is painted black, but that of B is not painted. The correct statement regarding this case is Show Answer

Q142) A piece of glass is heated to a high temperature and then allowed to cool. If it cracks, a probable reason for this is the following property of glass Show Answer

Q143) A body radiates energy 5W at a temperature of 127℃. If the temperature is increased to 927℃, then it radiates energy at the rate of Show Answer

Q144) In a radiation spectrum obtained from a furnace of 2600 K has maximum intensity at 12000 Å wavelength. If the maximum intensity in spectrum of a star is at 5000 A. the temperature of the outer surface of star is Show Answer

Q145) The point on the pressure-temperature phase diagram where all the three phases co-exist is called Show Answer

Q146) Distribution of energy in the spectrum of a black body can be correctly represented by Show Answer

Q147) A solid cube and a solid sphere of the same material have equal surface area. Both are at the same temperature 120℃, then Show Answer

Q148) If the initial temperatures of metallic sphere and disc, of the same mass, radius and nature are equal, then the ratio of their rate of cooling in same environment will be Show Answer

Q149) Colour of shinning bright star is an indication of its Show Answer

Q150) Water is used to cool the radiators of engines in cars because Show Answer

Q151) A closed bottle containing water at 30℃ is carried to the moon in a space-ship. If it is placed on the surface of the moon, what will happen to the water as soon as the lid is opened Show Answer

Q152) The factor not needed to calculate heat lost or gained when there is no change of state is Show Answer

Q153) A black metal foil is warmed by radiation from a small sphere at temperature and at a distance . It is found that the power received by the foil is . If both the temperature and the distance are doubled, the power received by the foil will be Show Answer

Q154) 16:1 The ratio of radiant energies radiated per unit surface area by two bodies is 16:1, the temperature of hotter body is 1000K, then the temperature of colder body will be Show Answer

Q155) It is difficult to cook rice in an open vessel by boiling it a high altitudes because of Show Answer

Q156) The variation of density of water with temperature is represented by the Show Answer

Q157) “Good emitters are good absorbers” is a statement concluded from Show Answer

Q158) Two vessels of different materials are similar in size in every respect. The same quantity of ice filled in them gets melted in 20 minutes and 30 minutes. The ratio of their thermal conductivities will be Show Answer

Q159) When the room temperature becomes equal to the dew point, the relative humidity of the room is Show Answer

Q160) The temperature of a piece of iron is 27℃ and it is radiating energy at the rate of Q kWm^(-2). If its temperature is raised to 151℃, the rate of radiation of energy will become approximately Show Answer

Q161) Two rods of same length and material transfer a given amount of heat in 12 s, when they are joined end to end (i.e, in series). But when they are joined in parallel, they will transfer same heat under same conditions in Show Answer

Q162) Heat is flowing through a conductor of length l from x=0 to x=l. If its thermal resistance per unit length is uniform, which of the following graphs is correct Show Answer

Q163) The wavelength of radiation emitted by a body depends upon Show Answer

Q164) The temperature of the sun is measured with Show Answer

Q165) By increasing the temperature of a liquid its Show Answer

Q166) If the temperature of the sun becomes twice its present temperature, then Show Answer

Q167) The temperature gradient in a rod of 0.5 m long is 80℃/m. If the temperature of hotter end of the rod is 30℃, then the temperature of the cooler end is Show Answer

Q168) For cooking the food, which of the following type of utensil is most suitable Show Answer

Q169) Good absorbers of heat are Show Answer

Q170) In heat transfer, which method is based on gravitation Show Answer

Q171) Which of the prism is used to see infra-red spectrum of light Show Answer

Q172) There is a rough black spot on a polished metallic plate. It is heated upto 1400 K approximately and then at once taken in a dark room. Which of the following statements is true Show Answer

Q173) Suppose the sun expands so that its radius becomes 100 times its present radius and its surface temperature becomes half of its present value. The total energy emitted by it then will increase by a factor of Show Answer

Q174) Two identical plates of different metals are joined to form a single plate whose thickness is double the thickness of each plate. If the coefficients of conductivity of each plate are 2 and 3 respectively, then the conductivity of composite plate will be Show Answer

Q175) When red glass is heated in dark room it will seen Show Answer

Q176) Wien’s displacement law for emission of radiation can be written as Show Answer

Q177) Amount of heat required to convert 10 g of ice to water at 20℃ is Show Answer

Q178) On investigation of light from three different stars A,B and C, it was found that in the spectrum of A the intensity of red colour is maximum, in B the intensity of blue colour is maximum and in C the intensity of yellow colour is maximum. From these observations it can be concluded that Show Answer

Q179) A body has same temperature as that of the surrounding. Then Show Answer

Q180) A substance of mass m kg requires a power input of P watts to remain in the molten state at its melting point. When the power is turned off, the sample completely solidifies in time t sec. What is the latent heat of fusion of the substance Show Answer

Q181) If the temperature of the sun were to increase from T to 2T and its radius from R to 2R, when the ratio of radiant energy received on earth to what it was previously, will be Show Answer

Q182) If the radius of a star is R and it acts as a black body, what would be the temperature of the star, in which the rate of energy production is Q Show Answer

Q183) Newton’s law of cooling holds good only, if the temperature difference between the body and the surroundings is Show Answer

Q184) A hot body will radiate heat most rapidly if its surface is Show Answer

Q185) It is hotter for the same distance over the top of a fire than it is in the side of it, mainly because Show Answer

Q186) When a copper ball is heated, the largest percentage increase will occur in its Show Answer

Q187) Two spheres of radii in the ratio 1:2 and densities in the ratio 2:1 and of same specific heat, are heated to same temperature and left in the same surrounding. Their rate of cooling will be in the ratio Show Answer

Q188) If a black body emits 0.5 J of energy per second when it is at 27℃, then the amount of energy emitted by it when it is at 627℃ will be Show Answer

Q189) If a graph is plotted taking the temperature in Fahrenheit along Y-axis and the corresponding temperature in Celsius along the X-axis, it will be a straight line Show Answer

Q190) The absolute temperatures of two black bodies are 2000 K and 3000 K respectively. The ratio of wavelengths corresponding to maximum emission of radiation by them will be Show Answer

Q191) A constant volume gas thermometer shows pressure reading of 50 cm and 90 cm of mercury at 0℃ and 100℃ respectively. When the pressure reading is 60 cm of mercury, the temperature is Show Answer

Q192) A hot and a cold body are kept in vacuum separated from each other. Which of the following cause decrease in temperature of the hot body Show Answer

Q193) An object is at a temperature of 400℃. At what temperature would it radiate energy twice as fast? The temperature of the surroundings may be assumed to be negligible Show Answer

Q194) Four rods of different radii r and length l are used to connect two reservoirs of heat at different temperatures. Which one will conduct heat fastest? Show Answer

Q195) A body initially at 80℃ cools to 64℃ in 5 min and to 52℃ in 10 min. the temperature of the surrounding is Show Answer

Q196) Which of the following cylindrical rods will conduct most heat, when their ends are maintained at the same steady temperature Show Answer

Q197) The thermal conductivity of a rod is 2. What is its thermal resistivity? Show Answer

Q198) Newton’s law of cooling is a special case of Show Answer

Q199) The spectral energy distribution of a star is maximum at twice temperature as that of sun. the total energy radiated by star is Show Answer

Q200) On a cold morning, a metal surface will feel colder to touch than a wooden surface because Show Answer

Q201) In which process, the rate of transfer of heat is maximum Show Answer

Q202) The thermal radiation from a hot body travels with a velocity of Show Answer

Q203) A vessel contains 110 g of water. The heat capacity of the vessel is equal to 10 g of water. The initial temperature of water in vessel in 10℃. If 220 g of hot water at 70C is poured in the vessel, the final temperature neglecting radiation loss will be Show Answer

Q204) Solids expand on heating because Show Answer

Q205) When a bimetallic strip is heated, it Show Answer

Q206) The temperature at which a black body ceases to radiate energy, is Show Answer

Q207) For an opeque body coefficient of transmission is Show Answer

Q208) If temperature of an object is 140⁰ F, then its temperature in centigrade is Show Answer

Q209) An amount of water of mass 20 g at 0℃ is mixed with 40 g of water 10℃, final temperature of the mixture is Show Answer

Q210) On the Celsius scale the absolute zero of temperature is at Show Answer

Q211) Mud houses are cooler in summer and warmer in winter because Show Answer

Q212) Mode of transmission of heat, in which heat is carried by the moving particles, is Show Answer

Q213) A constant pressure air thermometer gave a reading of 47.5 units of volume when immersed in ice cold water, and 67 units in a boiling liquids. The boiling point of the liquid will be Show Answer

Q214) In the Ingen Hauz’s experiment the wax melts up to lengths 10 and 25cm on two identical rods of different materials. The ratio of thermal conductivities of the two material is Show Answer

Q215) The amount of heat conducted out per second through a window, when inside temperature is 10℃ and outside temperature is -10℃, is 1000 J. Same heat will be conducted in through the window, when outside temperature -23℃ and inside temperature is Show Answer

Q216) The rate of radiation of a black body at 0℃ is EJ/s. The rate of radiation of this black body at 273℃ will be Show Answer

Q217) Calculate the amount of heat (in calories) required to convert 5 g of ice at 0℃ to steam at 100℃ Show Answer

Q218) There are two identical vessels filled with equal amounts of ice. The vessels are of different metals., If the ice melts in the two vessels in 20 and 35 minutes respectively, the ratio of the coefficients of thermal conductivity of the two metals is Show Answer

Q219) On heating, the temperature at which water has minimum volume is Show Answer

Q220) In a water-fall the water falls from a height of 100m. If the entire K.E. of water is converted into heat, the rise in temperature of water will be Show Answer

Q221) The dimensions of thermal resistance are Show Answer

Q222) A black body is at a temperature 300 K. It emits energy at a rate, which is proportional to Show Answer

Q223) The saturation vapour pressure of water at 100℃ is Show Answer

Q224) Hot water cools from 60℃ to 50℃ in the first 10 min and to 42℃ in the first 10 min and to 42℃ in the next 10 min. Then the temperature of the surroundings is Show Answer

Q225) A black body radiates 20 Wat temperature 227℃. If temperature of the black body is changed to 727℃ then its radiating power will be Show Answer

Q226) Mercury boils at 367°C.However,mercury thermometers are made such that they can measure temperature are made such that they can measure temperature upto 500°C.This is done by Show Answer

Q227) No other thermometer is as suitable as a platinum resistance thermometer to measure temperature in the entire range of Show Answer

Q228) Three identical rods A,B and C are placed end to end. A temperature difference is maintained between the free ends of A and C. The thermal productivity of B is thrice that if C and half of that of A. the effective thermal conductivity of the system will be (KA is the thermal conductivity of rod A) Show Answer

Q229) On Centigrade scale the temperature of a body increases by 30°.The increase in temperature on Fahrenheit scale is Show Answer

Q230) The Fahrenheit and Kelvin scales of temperature will give the same reading at Show Answer

Q231) Four rods of silver, copper, brass and wood are of same shape. They are heated together after wrapping a paper on it, the paper will burn first on Show Answer

Q232) In which mode of transmission, the heat waves travel along straight line with the speed of light? Show Answer

Q233) We consider the radiation emitted by the human body. Which of the following statements is true? Show Answer

Q234) Equal masses of two liquids are filled in two similar calorimeters. The rate of cooling will Show Answer

Q235) The wavelength of the radiation emitted by a body depends upon Show Answer

Q236) Two vessels of different materials are similar in size in every respect. The same quantity of ice filled in them gets melted in 20 minutes and 40 minutes respectively. The ratio of thermal conductivities of the materials is Show Answer

Q237) The intensity of radiation emitted by the sun has its maximum value at a wavelength of 510 nm and that emitted by the north star has the maximum value at wavelength of 350 nm. If these stars behave like black bodies, then the ratio of surface temperatures of the sun and north star is Show Answer

Q238) At NTP water boils at 100℃. Deep down the mine, water will boil at a temperature Show Answer

Q239) Two spheres of radii 8 cm and 2 cm are cooling. Their temperatures are 127℃ and 527℃ respectively. Find the ratio of energy radiated by them in the same time Show Answer

Q240) Expansion during heating Show Answer

Q241) The velocity of heat radiation in vacuum is Show Answer

Q242) The amount of work, which can be obtained by supplying 200 cal of heat, is Show Answer

Q243) The surface temperature of the stars is determined using Show Answer

Q244) The initial temperature of a body is 80℃. If its temperature falls to 64℃ in 5 minutes and in 10 minutes to 52℃ then the temperature of surrounding will be Show Answer

Q245) 80 gm of water at 30℃ are poured on a large block of ice at 0℃. The mass of ice that melts is Show Answer

Q246) On a hilly region, water boils at 95°C.The temperature expressed in Fahrenheit is Show Answer

Q247) Two thermometers A and B are exposed in sun light. The valve of A is pointed black, but that of B is not pointed. The correct statement regarding this case is Show Answer

Q248) When two ends of a rod wrapped with cotton are maintained at different temperatures and after same time every point of the rod attains a constant temperature, then Show Answer

Q249) Which of the following circular rods. (given radius r and length l) each made of the same material as whose ends are maintained at the same temperature will conduct most heat? Show Answer

Q250) 2 g of water condenses when passed through 40 g of water initially at 25℃. The condensation of steam raises the temperature of water to 54.3℃. What is the latent heat of steam? Show Answer

Q251) A block of ice at -10° c slowly heated and converted to steam at 100℃. Which of the following curves represents this phenomenon qualitatively? Show Answer

Q252) A thermos flask is polished well Show Answer

Q253) As compared to the person with white skin, the person with black skin will experience Show Answer

Q254) When the pressure on water is increased the boiling temperature of water as compared to 100℃ will be Show Answer

Q255) Which one of the figure gives the temperature dependence of density water correctly? Show Answer

Q256) In order that the heat flows from one part of a solid to another part, what is required Show Answer

Q257) The SI unit of mechanical equivalent of heat is Show Answer

Q258) A piece of blue glass heated to a high temperature and a piece of red glass at room temperature, are taken inside a dimly lit room then Show Answer

Q259) In determining the temperature of a distant star, one makes use of Show Answer

Q260) The energy supply being cut-off, an electric heater element cools down to the temperature of its
surroundings, but it will not cool further because Show Answer

Q261) Two spheres of radii 8 cm and 2 cm are cooling. Their temperatures are 127℃ and 527℃ respectively. Find the ratio of energy radiated by them in the same time. Show Answer

Q262) An iron bar of length l and having a cross-section A is heated from 0 to 100℃. If this bar is so held that it is not permitted to expand or bend, the force that is developed, is Show Answer

Q263) A black body is heated from 27℃ to 127℃. The ratio of their energies of radiations emitted will be Show Answer

Q264) Which of the following is the correct device for the detection of thermal radiation Show Answer

Q265) Two bodies A and B having temperatures 327℃ and 427℃ are radiating heat to the surrounding. The surrounding temperature is 27℃ . The ration of rate of heat radiation of A to that of B is Show Answer

Q266) In a steady state of thermal conduction, temperature of the ends A and B of a 20 cm long rod are 100℃ and 0℃ respectively. What will be the temperature of the rod at a point at a distance of 6 cm from the end A of the rod Show Answer

Q267) A vertical column 50 cm long at 50℃ balances another column of same liquid 60 cm long at 100℃. The coefficient of absolute expansion of the liquid is Show Answer

Q268) Absolute zero (0 K) is that temperature at which Show Answer

Q269) Absorption co-efficient of an open window is Show Answer

Q270) A perfect black body is one whose emissive power is Show Answer

Q271) Which one of the following would raise the temperature of 20 g of water at 30℃ most when mixed with it? Show Answer

Q272) A rectangular block is heated from 0℃ to 100℃. The percentage increase in its length is 0.2%. What is the percentage increase in its volume? Show Answer

Q273) Absolute temperature can be calculated by Show Answer

Q274) If temperature of a black body increases from 7℃ to 287℃, then the rate of energy radiation increases by Show Answer

Q275) If earth suddenly stops rotating about its own axis, the increase in it’s temperature will be Show Answer

Q276) The radiation emitted by star A is 10,000 times that of the sun. If the surface temperature of the sun and the star A are 6000k and 2000k respectively, the ratio of the radii of the star A and the sun is Show Answer

Q277) The temperature of a liquid drops from 365k to 361K in 2 minutes. Find the time during which temperature of the liquid drops from 344k to 342K. Temperature of room is 293K. Show Answer

Q278) Which of the following statements is correct Show Answer

Q279) Can we boil water inside the earth satellite by convection Show Answer

Q280) There is a black spot on a body. If the body is heated and carried in dark room then it glows more. This can be explained on the basis of Show Answer

Q281) Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. Assertion A When a rod lying freely is heated, no othermal stress is developed in it.
Reason R On heating, the length of the rod increases. In the light of the above statements, choose the correct answer from the options given below. Show Answer

Q282) A uniform cylindrical rod of length L and radius r, is made from a material whose Young's modulus of elasticity equals Y. When this rod is heated by temperature T and simultaneously subjected to a net longitudinal compressional force F, its length remains unchanged. The coefficient of volume expansion, of the material of the rod, is (nearly) equal to Show Answer

Q283) An external pressure p is applied on a cube at 0°C that it is equally compressed from all sides. K is the bulk modulus of the material of the cube and a is its coefficient of linear expansion. Suppose we want to bring the cube to its original size by heating. The temperature should be raised by Show Answer

Q284) A uniform metalic wire is elongated by 0.04 m when subjected to a linear force F. The elongation, if its length and diameter is doubled and subjected to the same force will be...... cm. Show Answer

Q285) The temperature of equal masses of three different liquids x, y and z are 10°C, 20°C and 30°C, respectively. The temperature of mixture when x is mixed with y is 16°C and that when y is mixed with z is 26°C. The temperature of mixture when x and z are mixed will be Show Answer

Q286) When 100 g of a liquid A at 100°C is added to 50 g of a liquid B at temperature 75°C, the temperature of the mixture becomes 90°C. The temperature of the mixture, if 100 g of liquid A at 100°C is added to 50 g of liquid B at 50°C will be Show Answer

Q287) Assume that a drop, of liquid evaporates by decrease in its surface energy. so that its temperature remains unchanged. What should be the minimum radius of the drop for this to be possible? The surface tension is T, density of liquid is p and L is its latent heat of vaporization. Show Answer

Q288) A body cools from 80°C to 60°C in 5 minutes. The temperature of the surrounding is 20°C. The time it takes to cool from 60°C to 40°C is Show Answer

Q289) A bowl filled with very hot soup cools from 98°C to 86°C in 2 minutes when the room temperature is 22°C. How long it will take to cool from 75°C to 69°C? Show Answer

Q290) Read the following statements.
A. When small temperature difference between a liquid and its surrounding is doubled, the rate of loss of heat of the liquid becomes twice.
B. Two bodies P and Q having equal surface areas are maintained at temperature 10°C and 20°C. The thermal radiation emitted in a given time by P and Q are in the ratio 1 : 1.15.
C. A carnot engine working between 100 K and 400 K has an efficiency of 75%.
D. When small temperature difference between a liquid and its surrounding is quadrupled, the rate of loss of heat of the liquid becomes twice.
Choose the correct answer from the options given below. Show Answer

Q291) A body takes 4 min to cool from 61° C to 59°C. If the temperature of the surroundings is 30°C, then the time taken by the body to cool from 51°C to 49° C is Show Answer

Q292) A metallic sphere cools from 50°C to 40°C in 300 s. If atmospheric temperature around is 20°C, then the sphere's temperature after the next 5 min will be close to Show Answer

Q293) A body takes 10 min to cool from 60°C to 50°C. The temperature of surroundings is constant at 25°C. Then, the temperature of the body after next 10 min will be approximately. Show Answer

Q294) A long metallic bar is carrying heat from one of its ends to the other end under steady-state. The variation of temperature 0 along the length x of the bar from its hot end is best described by which of the following figure. Show Answer

Q295) In 5 min, a body cools from 75°C to 65°C at room temperature of 25°C. The temperature of body at the end of next 5 min is ..... Show Answer