Tag: physics

Questions Related to physics

The speed at which the light travels in vacuum is.

physics reflection of light and shadow beam of light ray and beam ray optics

  1. $3 \times 10^{6} m/s $

  2. $3 \times 10^{8} m/s $

  3. $3 \times 10^{10} m/s $

  4. $3 \times 10^{12} m/s $

Show answer
Correct Option: B
Explanation:

The speed at which the light travels in vacuum is $ 3 \times 10^8 m/s$

If a parallel beam of light having intensity I is incident normally on a perfectly reflecting surface, the force exerted on the surface, equal F. When the surface is held at an angle $ \theta $ the force is 

physics reflection of light and shadow beam of light ray and beam ray optics

  1. $ 2F tan \theta $

  2. $ F cos \theta $

  3. $ F cos^2 \theta $

  4. $ 2 F $

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Correct Option: A

The shape of spot light produced when bright sunshine passes perpendicular through a hole of very small size, is:

physics reflection of light and shadow beam of light ray and beam ray optics

  1. Square because hole is square

  2. Round because it is an image of the sun

  3. Round with a small pinumbra around it

  4. Square with a small pinumbra

Show answer
Correct Option: B
Explanation:

  • The spots are often oval, rather than round. That's because the sunlight is hitting the ground at an angle and the round sun images are stretching out to make ovals.
  • It's perpendicular to the sun's rays, and the spots should become round. 
  •  Hence option B is the right answer

A light is said to be divergent when :

physics reflection of light and shadow beam of light ray and beam ray optics

  1. all the rays travel parallel to each other

  2. all the rays spread from a point source of light

  3. all the rays converge together to a single point

  4. it travels in an irregular pattern

Show answer
Correct Option: B
Explanation:

When the rays of light starting from a point travel in different directions, then the collection of such rays is termed as a divergent beam of light.

A light is said to be convergent when :

physics reflection of light and shadow beam of light ray and beam ray optics

  1. all the rays travel parallel to each other

  2. all the rays spread form a point source of light

  3. all the rays converge towards a single point

  4. it travels in an irregular pattern

Show answer
Correct Option: C
Explanation:

When the rays of light coming from different directions meet at a point, then the collection of such rays is termed as a convergent beam of light.

A narrow stream of light is called as :

physics reflection of light and shadow beam of light ray and beam ray optics

  1. Ray

  2. Beam

  3. Sunlight

  4. None of these

Show answer
Correct Option: A
Explanation:

Ray light is defined as each of the lines in which light (and heat) may seem to stream from the sun or any luminous body, or pass through a small opening.

A broad stream of light is called a :

physics reflection of light and shadow beam of light ray and beam ray optics

  1. Ray

  2. Beam

  3. Twilight

  4. Sunlight

Show answer
Correct Option: B
Explanation:

A broad stream of light is called a beam of light.
A beam is defined as a ray or stream of light or other radiation, as gamma rays, electrons, or subatomic particles.

State whether true or false.
When the rays of light starting from a point source travel in various directions, then the collection of such rays is called a convergent beam of light.

physics reflection of light and shadow beam of light ray and beam ray optics

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

When the rays of light starting from a point travel in various directions then collection of such rays is called divergent beam of light

A beam of light is made up of:

physics reflection of light and shadow beam of light ray and beam ray optics

  1. Rays

  2. Droplets

  3. Clusters

  4. Groups

Show answer
Correct Option: A
Explanation:
A $ \bf{beam\ of\ light}$ is group of rays of light travelling in a particular direction. 
A $ \bf{ray\ of\ light} $ is the direction along which the light energy propagates.

Hence, the correct answer is OPTION A.

State whether true or false:
In convergent beam of light all the light rays meet at a point.

physics reflection of light and shadow beam of light ray and beam ray optics

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

If a parallel beam of light fall on a converging mirror or lens then they will also pass through focus i.e. all the rays will meet at a point of a convergent beam.