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 maths position and movement reflection w.r.t a line transformation transformation and symmetry in geometrical shapes

A ray of light travelling along the line $x+\sqrt{3}y=5$ is incident on the $x-axis$ and after refraction it enters the other side of the $x-axis$ by turning $\dfrac{\pi}{6}$ away from the $x-axis$. The equation of the line along which the refracted ray travels is

  1. $x+\sqrt{3}y-5\sqrt{3}=0$
  2. $x-\sqrt{3}y-5\sqrt{3}=0$
  3. $\sqrt{3}x+y-5\sqrt{3}=0$
  4. $\sqrt{3}-y-5\sqrt{3}=0$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The incident ray x+sqrt(3)y=5 hits the x-axis at (5, 0) with slope -1/sqrt(3), which is -30 degrees. Refraction turns it 30 degrees away from the x-axis, making the new slope tan(30) = 1/sqrt(3). The line passes through (5, 0) with this slope.

Multiple choice maths position and movement reflection w.r.t a line transformation transformation and symmetry in geometrical shapes

A ray of light along $x + \sqrt {3y}  = \sqrt 3 $ gets reflected upon reaching $x - axis$ , then equation of the reflected ray is 

  1. $y = x + \sqrt 3 $
  2. $\sqrt 3 y = x - \sqrt 3 $
  3. $y = \sqrt 3 x - \sqrt 3 $
  4. $\sqrt 3 y = x - 1$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Mirror or reflecting surface/ boundary is $y = 0$ or $x-axis$.

Light Ray: $x + \sqrt3 y = \sqrt3$ or,
$\sqrt 3 y = \sqrt3 - x$.

Slope: $m = \dfrac{-1}{\sqrt3}$. Meets x axis at $A(\sqrt3, 0)$.

The reflected ray will have a slope$ = - m = \dfrac{1}{\sqrt3}$. Reason is that the angle of inclination with x axis becomes 180 - the angle of incident ray.

Also it passes through point $A$.

So the equation is: $y - 0 =\dfrac{ (x - \sqrt3)}{ \sqrt3}.$
Or, $\sqrt3 y - x + \sqrt3 = 0$.
Or, $\sqrt3 y=x-\sqrt3$

Multiple choice maths position and movement reflection w.r.t a line transformation transformation and symmetry in geometrical shapes

A ray light comming from the point $(1,2)$ is reflected at a point $A$ on the $x-$axis and then passes through the point $(5,3)$. The co-ordinates of the point $A$ is

  1. $\left(\dfrac {13}{5}, 0\right)$
  2. $\left(\dfrac {5}{13}, 0\right)$
  3. $(-7, 0)$
  4. $None\ of\ these$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Reflect (1, 2) across the x-axis to get (1, -2). The line connecting (1, -2) and (5, 3) intersects the x-axis at the point of reflection A.

Multiple choice maths position and movement reflection w.r.t a line transformation transformation and symmetry in geometrical shapes

A light ray gets reflected from the $ x= -2 $ .If the reflected ray touches the circle $ x^{2}+y^{2}=4 $ and point of incident is $(-2,-4)$,then equation of incident ray is

  1. $ 4y+3x+22=0 $
  2. $ 3y+4x+20=0 $
  3. $ 4y+2x+20=0 $
  4. $ y+x+6=0 $
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The incident ray reflects off x=-2. The reflected ray touches the circle x^2+y^2=4. Use the property that the incident ray, reflected ray, and normal at the point of incidence are related.

Multiple choice maths position and movement reflection w.r.t a line transformation transformation and symmetry in geometrical shapes

A ray of light along $x+\sqrt{3}y=\sqrt{3}$ get reflected upon reaching x-axis, the equation of the reflected ray is?

  1. $y=x+\sqrt{3}$
  2. $\sqrt{3}y=x-\sqrt{3}$
  3. $y=\sqrt{3}x-\sqrt{3}$
  4. $\sqrt{3}y=x-1$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The incident ray x+sqrt(3)y=sqrt(3) has slope -1/sqrt(3). It hits the x-axis at (sqrt(3), 0). The reflected ray will have slope 1/sqrt(3) and pass through (sqrt(3), 0). Equation: y-0 = 1/sqrt(3)(x-sqrt(3)) => sqrt(3)y = x-sqrt(3).

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

In dim light:

  1. rods are sensitive but cones are not

  2. cones are sensitive but rods are not

  3. both rods and cones are sensitive

  4. neither rods nor cones are sensitive
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Rods and cones are light sensitive cells. Rods respond to different degrees of brightness and darkness. Cones respond mainly to colour of the incident light.

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

Which of the following optical phenomena is used in cinematography or movie projectors?

  1. Accomodation

  2. Persistence of vision

  3. Long sightedness

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

Persistence of Vision is used in cinematography or movie projectors. Persistence of vision works because the human eye and brain can only process 10 to 12 separate images per second, retaining an image for up to a sixteenth of a second. If a subsequent image replaces it in this period of time it will create the illusion of continuity. Animation works by using an optical illusion. By presenting a sequence of still images in quick enough succession, the viewer interprets them as a continuous moving image. This is the same principle that enables live action film making and projection to work. Film theorists often refer to this illusion of movement as the persistence of vision.

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

If you read the words of your book, the reflection is

  1. specular reflection

  2. diffused reflection

  3. may be specular may be diffused

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Reading words from a book involves light reflecting off the surface in many directions so that it can be seen from various angles. This scattering of light is known as diffused reflection.

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

Image formation takes place by

  1. specular reflection

  2. diffused reflection

  3. Both (a) and (b)

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Image formation, such as in a mirror or through a lens, relies on the regular, predictable reflection or refraction of light rays. This is characteristic of specular reflection.

Multiple choice physics motion and measurement physical quantities units - definitions and systems physical quantities like mass and weight

Light travels at maximum speed in-

  1. Air

  2. Water

  3. Vacuum

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Light travels at approximately 300,000 kilometers per second in a vacuum, which has a refractive index of 1.0, but it slows down to 225,000 kilometers per second in water (refractive index = 1.3) and 200,000 kilometers per second in glass (refractive index of 1.5). The interaction of the light with the particles in the medius causes the delay.

Multiple choice physics spectra the electromagnetic spectrum electromagnetic spectrum electromagnetic waves

Electromagnetic waves exhibit the property of

  1. Reflection

  2. Refraction

  3. Total internal reflection

  4. Both A and B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

EM waves exhibit the properties of reflection and refraction. In refraction, when an EM wave passes from one medium to the another, its direction to travel,speed and wavelength changes, but frequency remains unchanged.

Multiple choice physics spectra the electromagnetic spectrum electromagnetic spectrum electromagnetic waves

Identify the most notable difference between a ultraviolet wave and a light wave ?

  1. Speed

  2. Refractive index

  3. Reflectivity

  4. Amplitude

  5. Frequency
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Both , ultraviolet and light wave are electromagnetic waves , having the speed of light , but in electromagnetic frequency spectrum ultraviolet wave falls before light wave , in the decreasing order of frequency.It means frequency of UV waves is greater than light wave.