Download App

Surface Tension — JEE physics STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 ScienceJEE physicsSurface Tension1 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 Surface Tension→Surface Tension — 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 : Resonance is special case of forced vibration in which the natural frequency of vibration of the body is the same as the impressed frequency of external periodic force and the amplitude of forced vibration is maximum.
Reason : The amplitude of forced vibrations of a body increases with an increase in the frequency of the externally impressed periodic force.
→
Assertion : In a S.H.M., kinetic and potential energies become equal when the displacement is $1 / \sqrt{2}$ times the amplitude.
Reason : In SHM, kinetic energy is zero when potential energy is maximum.
→
Assertion : The current gain in common base circuit is always less than one.
Reason : At constant collector voltage the change in collector current is more than the change in emitter current.
→
Assertion : It is necessary to use satellites for long distance T.V. transmission.
Reason : The television signals are low frequency signals.
→
Assertion : X-ray astronomy is possible only from satellites orbiting the earth.
Reason : Efficiency of $X$-rays telescope is large as compared to any other telescope.
→
Assertion : An object can have constant speed but variable velocity.
Reason : Speed is a scalar but velocity is a vector quantity.
→
Assertion : The speed of revolution of an artificial satellite revolving very near the earth is $8 \mathrm{kms}^{-1}$.
Reason : Orbital velocity of a satellite, become independent of height of near satellite.
→
Assertion : The apparent weight of a body in an elevator moving with some downward acceleration is less than the actual weight of body.
Reason : The part of the weight is spent in producing downward acceleration, when body is in elevator.
→
Assertion : In the relation $f=\frac{1}{2 l} \sqrt{\frac{T}{m}}$, where symbols have standard meaning, $m$ represent linear mass density.
Reason : The frequency has the dimensions of inverse of time.
→
Assertion : Red shift confirms that the universe is expanding
Reason : Wavelength of red light is maximum in the visible region
→