Tag: physics

Questions Related to physics

If light waves emitted by an ordinary source, for what period of time, the phase remains constant :-

  1. $10 sec$

  2. $1 sec$

  3. $10^{-3}$ sec

  4. $10^{-8}$ sec


Correct Option: B

According to Huygen's theory of light

  1. light is stream of photon

  2. light is wave

  3. light behaves as particle

  4. None of the above


Correct Option: B

In the case of parallel beam,

  1. intensity gradually increases

  2. intensity gradually decreases

  3. intensity remains constant

  4. None of these


Correct Option: D

Huygen's theory of light

  1. explain reflection and refraction of light

  2. explain scattering of light

  3. explain interference of light, diffraction of light

  4. None of the above


Correct Option: C

According to huygen's theory of secondary waves,following can be explained-

  1. Propagation of light in medium

  2. Reflection of light

  3. Refrection of light

  4. All of the above


Correct Option: A,B

Huygen's theory of secondary waves can be used of find-

  1. Velocity of light

  2. The wavelength of light

  3. Wave front geometrically

  4. Magnifying power of microscope


Correct Option: B

Huygen's theory of secondary waves can be used to find-

  1. Velocity of light

  2. The wavelength of light

  3. Wave front geometrically

  4. Magnifying power of microscope.


Correct Option: B

Coherent sources can be obtained:

  1. only by division of wave front

  2. only by division of amplitude

  3. both by division of amplitude and wave front

  4. none of the above


Correct Option: C

The wave theory in its original form was first postulated by 

  1. Issac Newton

  2. Thomas Young

  3. Christian Huygens

  4. Augustine Jean Fresnel


Correct Option: C
Explanation:

Christian Huygens postulated wave theory.

Assertion  $(A):$  Microwaves are better carries of signals than optical waves
Reason  $(R):$  Microwaves move faster than optical waves

  1. Both $A$ and $R$ are true and $R$ is correct explanation of $A$

  2. Both $A$ and $R$ are true and $R$ is not the correct explanation of $A$

  3. $A$ is true but $R$ is false

  4. $A$ is false but $R$ is true


Correct Option: D
Explanation:
A frequency of an optical wave is more than the microwave so optical waves are better canes of the signal, therefore, A is false. In medium (other than vacuum) speed of 0 microwaves 1A greater than optical wave hence R 1A true.
Ans. (D)