Download App

Work, Energy, Power and Collision — JEE physics STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 ScienceJEE physicsWork, Energy, Power and Collision1 Mark
Question
Assertion : Mass and energy are not conserved separately, but are conserved as a single entity called mass-energy.
Reason : Mass and energy conservation can be obtained by Einstein equation for energy.
✓

Answer

(a) From Einstein equation $E=m c^2$it can be observed that if mass is conserved then only energy is conserved and vice versa. Thus, both cannot be treated separately.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "Assertion & Reason" from Work, Energy, Power and Collision→Work, Energy, Power and Collision — all question types→JEE physics STD 12 Science question papers→CBSE Board STD 12 Science question papers→CBSE Board question paper generator→

Similar questions

Assertion : The presence of water molecules makes separation of ions easier in electrolyte.
Reason : The presence of water molecules in electrolyte decreases the resistance of electrolyte.
→
Assertion : An adiabatic process is an isoentropic process.
Reason : Change in entropy is zero in case of adiabatic process.
→
Assertion : A bullet is fired from a rifle. If the rifle recoils freely, the kinetic energy of rifle is more than that of the bullet.
Reason : In the case of rifle bullet system the law of conservation of momentum violates.
→
Assertion : We can measure the potential barrier of a $P N$ junction by putting a sensitive voltmeter across its terminals.
Reason : The current through the $P N$ junction is not same in forward and reversed bias.
→
Assertion : If two protons are brought near one another, the potential energy of the system will increase.
Reason : The charge on the proton is $+1.6 \times 10^{-19} \mathrm{C}$.
→
Assertion : The rate of change of total momentum of a many particle system is proportional to the sum of the internal forces of the system.
Reason : Internal forces can change the kinetic energy but not the momentum of the system.
→
Assertion : The average speed of a body over a given interval of time is equal to the average velocity of the body in the same interval of time if a body moves in a straight line in one direction.
Reason : Because in this case distance travelled by a body is equal to the displacement of the body.
→
Assertion : Sudden fall of pressure at a place indicates strom.
Reason : Air flows from higher pressure to lower pressure.
→
Assertion : When the force retards the motion of a body, the work done is zero.
Reason : Work done depends on angle between force and displacement.
→
Assertion : Two identical solid balls, one of ivory and the other of wet-clay are dropped from the same height on the floor. Both the balls will rise to same height after bouncing.
Reason : lvory and wet-clay have same elasticity.
→