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 physics spectra the electromagnetic spectrum electromagnetic spectrum electromagnetic waves

Which of the following light has the combination of all frequencies of visible light ?

  1. white light

  2. black light

  3. ultraviolet light

  4. infrared light

  5. transparency
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The visible light contains 7 colours  :  Violet, indigo, Blue, Green, Yellow, Orange and Red.

White colour is formed by the interference of all 7 colours, thus white light has the combination of all frequencies of visible light.

Multiple choice physics spectra the electromagnetic spectrum electromagnetic spectrum electromagnetic waves

Identify which of the following is NOT a source of visible light?

  1. red-hot metal

  2. cool metal

  3. fluorescent bulb

  4. the Sun

  5. fire
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When the electrons in the atom are excited, for example by being heated, the additional energy pushes the electrons to higher energy orbits. When the electrons fall back down and leave the excited state, energy is re-emitted in the form of a photon.

Thus the hot objects release photons that have energies lying in the visible region. However photons from cool metal do not have energy enough to lie in visible region.

Multiple choice physics spectra the electromagnetic spectrum electromagnetic spectrum electromagnetic waves

Electromagnetic waves that include light belong to

  1. light spectrum.

  2. electronic spectrum.

  3. electromagnet group.

  4. electromagnetic spectrum.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Electromagnetic waves do not include light belong to electromagnetic spectrum.

The the basic source of electromagnetic waves is an accelerated charge. This produces the changing electric and magnetic field which constitutes electromagnetic wave. An electromagnetic wave may have its wavelength varying from zero to infinity. The classification of electromagnetic waves according to frequency or wavelength is called the electromagnetic spectrum.

Multiple choice physics human eye and colourful world human eye and its working what is inside our eyes? human eye and defects of vision

We are able to see objects around us because :

  1. The objects absorb all the light.

  2. The light reflected from the object enters our eyes.

  3. Light can be refracted.

  4. Light travels in straight lines.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

We are able to see objects around us because the light reflected from the object enters our eyes.

Multiple choice physics pressure in fluids and atmospheric pressure pressure in air introduction to atmospheric pressure pressure exerted by air devices to measure pressure

A glass bulb is balanced by a brass weight in a sensitive beam balance. Now the balance is covered by a glass-jar which is then evacuated. Then:

  1. the beam will remain horizontal

  2. the pan containing the bulb will go down

  3. the pan containing the bulb will go

  4. none of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Given, That a glass bulb is balanced by a brass weight in a sensitive beam balance,

Now the balance is covered by a glass jar which is then evacuated.
By evacuating, there will be no air in the glass jar. so the glass bulb will be higher in mass because it contains air inside the glass bulb,
So the pan containing the bulb will go down
Therefore the correct option is $B$

Multiple choice physics electrical circuits domestic electric circuits and safety precautions domestic and commercial circuit electric power

How the small bulbs, which are used for decoration purpose,are connected?

  1. in parallel

  2. in series

  3. in mixed order

  4. all of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Bulbs used for decoration purposes are connected end to end, that is, in series. This ensures that same amount of current flows through them and the voltage divides across the bulbs as required for low voltage operation. Thus when one bulb goes out, due to being in series, all the bulbs stop glowing.

Multiple choice physics quantum physics photons concept of photon photons and photoelectric effect

A laser beam ($\iota = 633\ nm$)has an power of $3mW$. What will be the pressure exerted on a surface by this beam if the cross sectional area is $3\ mm^{2}$ (Assume perfect reflection and normal incidence)

  1. $6.6\times 10^{-3}N/m^{2}$
  2. $6.6\times 10^{-6}N/m^{2}$
  3. $6.6\times 10^{-9}N/m^{2}$
  4. $6.6\ N/m^{2}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Pressure P = (2 * I) / c for perfect reflection. Intensity I = Power / Area = 3e-3 / 3e-6 = 1000 W/m^2. P = 2 * 1000 / 3e8 = 6.66e-6 N/m^2.