Practice Test

Q1) When a 4V battery is connected across an unknown resistor there is a current of 100 mA in the circuit. The value of the resistance of the resistors is: Show Answer

Q2) Unit of electric power may also be expressed as: Show Answer

Q3) Electrical resistivity of a given metallic wire depends upon Show Answer

Q4) The resistivity does not change if: Show Answer

Q5) Two bulbs of 100 W and 40 W are connected in series. The current through the 100 W bulb is 1 A. The current through the 40 W bulb will be: Show Answer

Q6) Which of the following represents voltage? Show Answer

Q7) In an electrical circuit three incandescent bulbs A, B, and C of rating 40 W, 60 W, and 100 W, respectively are connected in parallel to an electric source. Which of the following is likely to happen regarding their brightness? Show Answer

Q8) Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as:
Assertion (A): The resistivity of conductor increases with the increasing of temperature.
Reason (R): The resistivity is the reciprocal of the conductivity. Show Answer

Q9) Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as:
Assertion (A): Bending a wire does not affect electrical resistance.
Reason (R): Resistance of wire is proportional to resistivity of material. Show Answer

Q10) Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as:
Assertion (A): Alloys are commonly used in electrical heating devices like electric iron and heater.
Reason (R): Resistivity of an alloy is generally higher than that of its constituent metals but the alloys have low melting points then their constituent metals. Show Answer

Q11) Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as:
Assertion (A): In a simple battery circuit the point of lowest potential is positive terminal of the battery.
Reason (R): The current flows towards the point of the lower potential as it flows in such a circuit from the positive to the negative terminal. Show Answer

Q12) Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as:
Assertion (A): Electric appliances with metallic body have three connections, whereas an electric bulb has a two pin connection.
Reason (R): Three pin connections reduce heating of connecting wires. Show Answer

Q13) Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as:
Assertion (A): The electric bulbs glow immediately when switch is ON.
Reason (R): The drift velocity of electrons in a metallic wire is very high. Show Answer

Q14) Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as:
Assertion (A): Copper is used to make electric wires.
Reason (R): Copper has very low electrical resistance. Show Answer

Q15) Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as:
Assertion (A): Silver is not used to make electric wires.
Reason (R): Silver is a bad conductor. Show Answer

Q16) Which of the following is the correct circuit diagram to connect all the devices in proper correct order. Show Answer

Q17) How much is the total resistance? Show Answer

Q18) The device used to measure the current: Show Answer

Q19) Which of the following is connected in series in circuit: Show Answer

Q20) Which is a better conductor? Show Answer

Q21) Element used to make heating element of electric geyser: Show Answer

Q22) Element used to make filament of incandescent bulb: Show Answer

Q23) What happens to resistance of a conductor when its area of cross section is increased? Show Answer

Q24) A given length of a wire is doubled and this process is repeated once again. The resistance of wire becomes: Show Answer

Q25) Which is a better conductor of electric current? Show Answer

Q26) Which element will be used for electrical transmission lines? Show Answer

Q27) Nichrome is used in the heating elements of electric heating device because: Show Answer

Q28) Series arrangement is not used for domestic circuits because: Show Answer

Q29) If the resistance is to be increased, then the resistors are to be increased in: Show Answer

Q30) When this experiment is repeated by inserting another nichrome wire of the same thickness but twice the length (2L), what changes are observed in the ammeter reading? Show Answer

Q31) State the changes that are observed in the ammeter reading if we double the area of cross-section without changing the length in the above experiment. Show Answer

Q32) The instrument used to measure current is _______. Show Answer

Q33) If the wattage of each bulb is 1.5 W, how much readings will the ammeter A show when all the three bulbs glow simultaneously. Show Answer

Q34) Find the total resistance of the circuit. Show Answer

Q35) How many resistors of 88 W are connected in parallel to carry 10 A current on a 220 V line? Show Answer

Q36) Find the statement which does not justify parallel connection: Show Answer

Q37) which of these circuit diagram shows the correct connection when A and B are joined in parallel? Show Answer

Q38) In which combination will the voltage across the conductors A and B be the same? Show Answer

Q39) In which arrangement will the current through A and B be the same. Show Answer

Q40) Equivalent resistance in parallel combination is: Show Answer

Q41) Equivalent resistance in series combination is: Show Answer

Q42) Effective resistance of two 8Ω resistors in the combination. Show Answer

Q43) Power dissipated in 4Ω resistor is: Show Answer

Q44) The resistivity does not change, if Show Answer

Q45) Specific resistance of a conductor increases on increasing its temperature. Show Answer

Q46) The substance which have a higher value of resistance and small number of free electrons in it, is called Show Answer

Q47) The filament of bulb is made up of Show Answer

Q48) The rate at which energy is delivered by a current is determined by Show Answer

Q49) Assertion: Longer wires have greater resistance and the smaller wires have lesser resistance.
Reason: Resistance is inversely proportional to the length of the wire. Show Answer

Q50) Assertion: The connecting wires are made of copper.
Reason: The electrical conductivity of copper is high. Show Answer

Q51) Assertion: When the resistances are connected end-to-end consecutively, they are said to be in series.
Reason: In case the total resistance is to be decreased, then the individual resistances are connected in parallel. Show Answer

Q52) Assertion: The fuse is placed in series with the device.
Reason: Fuse consists of a piece of wire made of a metal or an alloy of appropriate melting point. Show Answer

Q53) Assertion: The 200 W bulbs glow with more brightness than 100 W bulbs.
Reason: A 100 W bulb has more resistance than 200 W bulb. Show Answer

Q54) Which one of the following is the correct set-up for studying the dependence of the current on the potential difference across a resistor? Show Answer

Q55) In an electrical circuit three incandescent bulbs, A,B and C of rating 40W, 60W and 100W, respectively are connected in parallel to an electric source. Which of the following is likely to happen regarding their brightness? Show Answer

Q56) Which of the following obeys ohm's law? Show Answer

Q57) Two bulbs have the following ratings
(i) 40 W, 220 V (ii) 20 W, 110 V
The ratio of their resistances is Show Answer

Q58) At the time of short circuit, the electric current in the circuit Show Answer

Q59) Materials which follow Ohm's law are Show Answer

Q60) The slope of V - 1 graph (V on x-axis and I on y-axis) gives Show Answer

Q61) Assertion at high temperatures, metal wires have a greater chance of short circuiting
Reason both resistance and resistivity of a material vary with temperature. Show Answer

Q62) By increasing the voltage across a conductor, the Show Answer

Q63) Assertion incandescent bulb passes an electric current through a metal filament to produce heat.
Reason the higher the wattage, the more energy is consumed. Show Answer

Q64) Assertion heater wire must have high resistance and high melting point.
Reason if resistance is high, the electric conductivity will be less. Show Answer

Q65) when a 9 V battery is connected across a conductor and the current flows is 0.1 A, the resistance is Show Answer

Q66) For insulator at room temperature, the graph between V and I is given. Which one is correct? Show Answer

Q67) The SI unit of electric energy per unit time is Show Answer

Q68) The energy dissipated by the heater is E. When the time of operating the heater is doubled the energy dissipated is Show Answer

Q69) The power of a lamp is 60W. The energy consumed in 1 minute is Show Answer

Q70) Kilowatt - hour is equal to Show Answer

Q71) To get 2 Ω resistance using only 6Ω resistor, the number of them required is Show Answer

Q72) Two devices are connected two points say A and B in parallel. The physical quantity that will remain the same between the two points is Show Answer

Q73) The least resistance obtained by using 2 Ω, 4 Ω, 1 Ω and 100 Ω is Show Answer

Q74) Two resistor are connected in series gives an equivalent resistance of 10 Ω . When connected in parallel, gives 2.4 Ω. Then the individual resistance are Show Answer

Q75) The resistance of hot filament of the bulb is about 10 times the cold resistance. What will be the resistance of 100 W-220 V lamp, when not in use? Show Answer

Q76) A coil in the heater consume power P on passing current. If it is cut into halves and joined in parallel, it will consume power Show Answer

Q77) A fuse wire repeatedly gets burnt when used with a good heater. It is advised to use a fuse wire of Show Answer

Q78) A cooler of 1500 W, 200 volt and a fan of 500 W, 200 volt are to be used from a household supply. The rating of fuse to be used is Show Answer

Q79) A current of 1 A is drawn by a filament of an electric bulb. Number of electrons passing through a cross-section of the filament in 16 seconds would be roughly Show Answer

Q80) What is the maximum resistance which can be made using five resistors each of 1/5 W? Show Answer

Q81) If the current I through a resistor is increased by 100% (assume that temperature remains unchanged), the increase in power dissipated will be Show Answer

Q82) The resistivity does not change if Show Answer

Q83) In an electrical circuit two resistors of 2 Ωand 4 Ω respectively are connected in series to a 6 V battery. The heat dissipated by the 4 Ω resistor in 5 s will be Show Answer

Q84) Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as:

Assertion (A): When a battery is short circulated, the terminal voltage is zero.
Reason (R): In short circuit, the current is zero. Show Answer

Q85) Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as:

Assertion (A): Conductors allow the current to flow through themselves.
Reason (R): They have free charge carriers. Show Answer

Q86) Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as:

Assertion (A): In an open circuit, the current passes from one terminal of the electric cell to another.
Reason (R): Generally, the metal disc of a cell acts as a positive terminal.
Show Answer

Q87) Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as:

Assertion (A): The statement of Ohm's law is V = IR
Reason (R): V=IR is the equation which defines resistance.
Show Answer

Q88) Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as:

Assertion (A): Bending of wire decrease the resistance of electric wire.
Reason (R): The resistance of a conductor depends on length, thickness, nature of material and temperature of the conductor.
Show Answer

Q89) Rheostat used in series in a circuit can make a bulb to glow with varying brightness. Show Answer

Q90) One common point and no sharing devices for that point are the conditions to be satisfied for two resistor to be in series. Show Answer

Q91) Nichrome is used for making standard resistances as it readily varies its resistance with temperature. Show Answer

Q92) When bulb are connected in series, the lower power bulb glows brighter. Show Answer

Q93) The equivalent resistance between two diametrically opposite points as a wire of 10 Ω resistance is made a circle is 2.5 Ω. Show Answer

Q94) Devices of higher power used at home have lower resistance. Show Answer

Q95) 12 V means the work done to carry a unit charge from one point to another is 2 joule. Show Answer