Practice Test

Q1) SI unit of work is Show Answer

Q2) The ratio of SI to cgs units of work is Show Answer

Q3) Area under the force-displacement graph represents Show Answer

Q4) Work done by force of friction is Show Answer

Q5) Work done by centripetal force displacing a particle along a circular path is Show Answer

Q6) When a car moves a uniform speed over a frictionless road, work done is Show Answer

Q7) Choose the wrong statement : Show Answer

Q8) The time rate of doing work by a body is called Show Answer

Q9) SI unit of power is Show Answer

Q10) The practical unit of power is Show Answer

Q11) 1 horse power is equal to Show Answer

Q12) Which of the following is not the unit of energy ? Show Answer

Q13) 1 e V is equal to Show Answer

Q14) 1 kilo watt hour (kWh) is equal to Show Answer

Q15) The linear momentum (p) and kinetic energy (E) for a body of mass m are related as Show Answer

Q16) The dimensional representation for work done by a force is given by Show Answer

Q17) The dimensional formula for work done by a centripetal force is Show Answer

Q18) The energy stored in a system by virtue of its configuration is called Show Answer

Q19) When a machine gun fires n bullets per second, each with kinetic energy K, then the power of machine gun is Show Answer

Q20) The energy associated with state of compression or expansion of an elastic spring is called its Show Answer

Q21) The slope of work-time curve at any instant represents Show Answer

Q22) When linear momentum of a body becomes n times, its kinetic energy becomes Show Answer

Q23) When water is flowing through a pipe with speed v, then its power is proportional to Show Answer

Q24) The power dissipated by centripetal force is Show Answer

Q25) A body at rest may have Show Answer

Q26) When current I flows through an inductor of inductance L, then magnetic energy stored in the inductor is given by Show Answer

Q27) When a capacitor of capacity C is charged to potential V, then electrostatic energy stored in the capacitor is given by Show Answer

Q28) When an electric circuit draws I ampere current at a potential difference of V volt, then electric energy consumed in t second is given by (in joule) Show Answer

Q29) For a perfectly elastic collision, the coefficient of restitution (e) is Show Answer

Q30) For a perfectly inelastic collision, the coefficient of restitution or resilience of two bodies (e) is Show Answer

Q31) A long spring is stretched by 2 cm and its potential energy is U. If the spring is stretched by 10 cm, the potential energy stored in it will be Show Answer

Q32) A person is riding on a cycle with a velocity 7.2 km/hr up a hill having a slope 1 in 20. If total mass of the man and cycle is 100 kg, then the power of man is Show Answer

Q33) If two protons are brought near one another, the potential energy of the system will Show Answer

Q34) A body is under the action of two equal and opposite forces, each of 5N. The body is displaced by 3 m. The work done is Show Answer

Q35) The work done on a body does not depend upon Show Answer

Q36) A boy holds a box of weight 40 N. he walks 5 m along the horizontal and then climbs up a vertical distance of 3 m. The work done by the boy is Show Answer

Q37) Two bodies P and Q having masses in the ratio 3:1 posses the same kinetic energy. The ratio of linear momentum of Q to P is Show Answer

Q38) A particle is describing a horizontal circle of radius 0.8 m with uniform speed. The centripetal force acting on the particle is 20 N. Then the work done in describing a semi-circle is Show Answer

Q39) The same retarding force is applied to stop a train. The train stops after 40 m. When the speed is doubled, the train will cover a distance of Show Answer

Q40) The work done by the external forces on a system equals he change in Show Answer

Q41) Which of the following is different from others ? Show Answer

Q42) A force of 5 N acts through a distance 20 m in the direction of motion. The work done is Show Answer

Q43) A bullet fired into a target loses half its velocity after penetrating 20 cm. How much further will it penetrate before coming to rest ? Show Answer

Q44) Two spheres of the same diameter, one of mass 4 kg and the other 1 kg are dropped at the same time from the top of a tower. When they are 1 m above the ground, the two spheres have the same Show Answer

Q45) A body has a box of weight 20 kg. Then the energy of the box when he keeps the box in his hand for 5 min is Show Answer

Q46) What is the shape of the graph between the speed and kinetic energy of a body ? Show Answer

Q47) When you lift a box from the floor and keep it on the table, the work done by you on the box depends on Show Answer

Q48) A body of constant momentum must always Show Answer

Q49) A motor of 200 H.P. moves with a uniform speed of 72 km/hr. The forward thrust applied by the engine on the car is Show Answer

Q50) A body of mass m accelerates uniformly from rest to a speed v in time t second. The average power delivered is Show Answer

Q51) A metallic wire of length L metre extends by l metre when stretched by suspending a weight mg from it. The mechanical energy stored in the wire is Show Answer

Q52) A motor of vacuum cleaner has a rating 600 W. The amount of work done in one minute is Show Answer

Q53) 1 amu mass is equal to Show Answer

Q54) Assertion :
Linear momentum is conserved in both elastic and inelastic collisions.
Reason:
Total energy is conserved in all such collisions. Show Answer

Q55) Assertion :
Kilowatt hour is the unit of electric power.
Reason :
Watt hour has units of energy. Show Answer

Q56) Assertion :
No work is done when an electron completes a circular orbit around the nucleus of an atom.
Reason :
Work done by a centripetal force is always zero. Show Answer

Q57) Which of the following graphs best represents the variation between kinetic energy (E) and linear momentum (p) ? Show Answer

Q58) A particle, initially at rest on a frictionless horizontal surface, is acted upon by a horizontal force which is constant in magnitude and direction. A graph is plotted of work done (W) on the particle, against the speed (v) of the particle. If there are no other horizontal forces acting on the particle, the graph will look like Show Answer

Q59) The SI units, the number of basic physical quantities are Show Answer

Q60) Light year represents Show Answer

Q61) If the energy E of a photon is equal to hv, where v is the frequency and h is Planck's constant, then the dimensions of Plank's constant is Show Answer

Q62) Which one of the following is a dimensionless quantity ? Show Answer

Q63) Dyne x second stands for the unit of Show Answer

Q64) A projectile is fired at an angle theta with the horizontal in a resistance free atmosphere. Which of the following quantities does not change during its motion ? Show Answer

Q65) Assertion (A): A gun recoils when a bullet is fired from it.
Reason (R): Action and reaction are equal and opposite. Show Answer

Q66) If the momentum of a body increases by 20%, then its kinetic energy will increase by Show Answer

Q67) Which one of the following diagrams illustrates the relation between kinetic energy (K) and the velocity (V) of a body ? Show Answer

Q68) Which of the following are the characteristics of an inelastic collision ?
(1) Momentum is conserved.
(2) Total energy is conserved.
(3) Kinetic energy is conserved.
(4) All the forces must be of conservative nature.
Choose the correct answer from the codes given below: Show Answer

Q69) The proper use of lubricants cannot reduce Show Answer

Q70) A rod of mass m and length l is lying on A horizontal table. Work done in making it stand on one end will be
Show Answer

Q71) When the kinetic energy of body is increased by 300%, the momentum of the body is increased by
Show Answer

Q72) A 4 kg mass and a 1 kg mass are moving with equal kinetic energies. The ratio of their momenta is
Show Answer

Q73) Fast neutrons can easily be slowed down by
Show Answer

Q74) Which one of the following statements correctly defines power ?
Show Answer

Q75) The power output of a machine that lifts a 600 kg weight through a height of 20 m in 1 min is
Show Answer

Q76) A particle is moving freely. Then its Show Answer

Q77) A body initially at rest is acted upon by a constant force. The rate of change of its kinetic energy varies
Show Answer

Q78) A body is at rest on the surface of the earth. Which one among the following statements is correct regarding this ? Show Answer