Tag: light and shadow

Quizzes (9) Questions (122)

Questions Related to light and shadow

Multiple choice physics light and shadow formation of image by a pinhole camera pinhole camera shadow

A ray of sunlight enters a spherical water droplet $(n = \dfrac{4}{3})$ at an angle of incidence $53^\circ$ measured with respect to the normal to the surface. It is reflected from the back surface of the droplet and re-enters into air. The angle between the incoming and outgoing ray is [Take $\sin \ 53^\circ = 0.8$]

  1. $15^\circ$
  2. $127^\circ$
  3. $138^\circ$
  4. $30^\circ$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The angle between the incoming and outgoing ray is $180^o-53=127$.

Multiple choice physics light and shadow formation of image by a pinhole camera pinhole camera shadow

A small plane mirror kept at the centre of a sphere of diameter $3\ m$, makes $12$ revolution per second. A thin light beam is made incident on the mirror. The linear speed of the light spot on the sphere, formed after reflection from the mirror is :

  1. $18\pi\ m/s$
  2. $36\pi\ m/s$
  3. $72\pi\ m/s$
  4. $144\pi\ m/s$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

When plane mirror rotates through an angle $\theta$ , the reflected ray rotates through an angle 2$\theta$. So spot on the screen will make 2 x 12 = 24  revolution per second.

 
To find the velocity 
v=2$\pi$R x frequency 
=2$\pi$ x 3 x 24
=144$\pi$ m/s

 D is the Correct answer.
 

Multiple choice physics light and shadow formation of image by a pinhole camera pinhole camera shadow

Intensity of light due to a point source at a distance $2m$ is $20$ units. The intensity due to the same source at a distance of $4m$ is

  1. $2.5\ units$
  2. $6\ units$
  3. $80\ units$
  4. $5\ units$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Intensity follows the inverse square law, I proportional to 1/r^2. If distance doubles from 2m to 4m, intensity becomes 1/4 of the original value: 20 / 4 = 5 units.

Multiple choice physics light and shadow formation of image by a pinhole camera pinhole camera shadow

Light has a wave nature,because-

  1. The light travel in a straight line

  2. Light exhibits phenomenon of reflection and refraction

  3. Lights phenomeno interference

  4. Light exhibits phenomeno of photo electric effect
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Wave nature of light is demonstrated by wave phenomena like interference, diffraction, and polarization. Interference (superposition of waves creating patterns of constructive and destructive interference) cannot be explained by particle theory. Photoelectric effect (option D) demonstrates particle nature, not wave nature. Reflection and refraction can be explained by both theories.

Multiple choice physics light and shadow formation of image by a pinhole camera pinhole camera shadow

Which one statement is correct -

  1. Speed of light in free space $= \frac{1}{\sqrt{\mu _0 \varepsilon _0}}$
  2. Speed of light in any medium $=\frac{1}{\sqrt{\mu \varepsilon}}$
  3. $\frac{E _0}{B _0}=2C$
  4. $\frac{B _0}{E _0}=4C$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The speed of light in free space is given by c = 1 / sqrt(mu_0 * epsilon_0), which is a fundamental result of Maxwell's equations.

Multiple choice physics light and shadow formation of image by a pinhole camera pinhole camera shadow

Light falls on a plane reflecting surface. For what angle of incidence is the reflected ray normal to the incident ray. 

  1. $60^o$
  2. $45^o$
  3. $90^o$
  4. $30^o$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The incident ray will have an angle of reflection of ${30^0}$ $($made with a surface normal to the mirror surface$).$

Hence,
option $(D)$ is correct answer.

Multiple choice evs light and shadow nature and sources of light how light travels path of light elementary ideas of astronomy

The colour of a green leaf, when white light passing through a yellow filter is applied on it is:

  1. black

  2. yellow

  3. red

  4. green
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A yellow filter allows only yellow colour to pass through it. A leaf looks green because leaf reflects green colour and absorbs the rest. Thus, the yellow light passing through the filter will be absorbed by the green leaf. Thus, no colour will be reflected by the leaf making it appear black.

Multiple choice evs light and shadow nature and sources of light how light travels path of light elementary ideas of astronomy

A beam of light gets reflected from a plane mirror and a real image is formed. The incident beam should be 

  1. Parallel

  2. Convergent

  3. Divergent

  4. Plane mirror cannot form a real image
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

  1. Plane mirrors don't usually form real images They form virtual images of real objects. However, things can be arranged so that a plane mirror does form a real image. A convergent light beam can do this. So the answer is "convergent"

  2. When at convergence point, a convergent beam of light is incident on the plane mirror, a real image is formed at the point