Physics · Science General

Optics and Light Properties

2,019 Questions

Optics and light properties focus on the behavior of light, including reflection, refraction, dispersion, and polarization. This topic also covers the wave nature of light, illumination, and the functioning of optical instruments like microscopes. Questions on these concepts are common in general science sections of SSC, Railways, and State exams.

Reflection and mirrorsRefraction and mediumsLight wave theoriesPolarization and intensity

Optics and Light Properties Questions

Multiple choice

When red light falls on green leaf and red flower, they become ____.

  1. green leaf and red flower

  2. red leaf and red flower

  3. black leaf and red flower

  4. leaf and black flower
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When red light falls on objects, the color we see depends on what light each object absorbs or reflects. A green leaf appears green because it absorbs red light and reflects green. Therefore, under red light, the green leaf absorbs all the red and appears black. A red flower reflects red light, so it continues to appear red under red light.

Multiple choice

The sky of the earth appears to be blue because of ____.

  1. reflection

  2. scattering

  3. interference

  4. diffraction
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Blue light is scattered most by air molecules due to Rayleigh scattering (scattering intensity ~1/λ^4). Reflection would bounce light back unchanged, while interference and diffraction don't cause the sky's blue color.

Multiple choice

What is the use of extra yellow head lights of a car?

  1. Yellow light expands less energy.

  2. Yellow light does not make the pedestrian blind.

  3. Yellow light can penetrate the fog so on a foggy day road becomes clear.

  4. To decorate the car.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Yellow light has a longer wavelength that scatters less in fog compared to white light (Rayleigh scattering decreases with longer wavelength). This gives better penetration through fog particles, improving visibility. Yellow light also causes less eye strain than white light.

Multiple choice

One important difference between light and sound is that the former _____.

  1. is a wave motion

  2. can be reflected

  3. can bend round corners

  4. can travel through space

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Light is an electromagnetic wave that can travel through vacuum (empty space), which is why we receive sunlight. Sound is a mechanical wave that requires a material medium (solid, liquid, or gas) to propagate - it cannot travel through space. Both can be reflected and can bend around corners (diffraction), so the key distinction is the ability to travel through vacuum.

Multiple choice

When angle of incidence is equal to the critical angle, the angle of refraction is _____.

  1. 0°

  2. 90°

  3. 145°

  4. 180°
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

At the critical angle, the refracted ray grazes along the boundary between the two media, making an angle of 90° with the normal. This is the defining condition for total internal reflection - when the angle of incidence equals or exceeds the critical angle, light can no longer enter the second medium.

Multiple choice

Formation of shadow proves that ____.

  1. light moves in a straight line

  2. light is an eletromagnetic wave

  3. light is a particle

  4. light does not undergo diffraction
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Shadows form because light travels in straight lines and cannot bend around opaque objects. When an object blocks light, a dark region (shadow) forms behind it where light cannot reach, demonstrating rectilinear propagation of light.

Multiple choice

The blue colour of the sky is due to

  1. diffuse sky radiation

  2. emission

  3. cosmic dust

  4. rayleigh scattering

  5. polarisation
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Due to Rayleigh scattering, the sky looks blue.