Physics

Light and Mirrors

458 Questions

Light and mirrors questions cover the principles of reflection, image formation, and mirror magnification. Concepts include the properties of plane mirrors, the uses of concave mirrors in solar devices, and the behavior of light rays. These fundamentals are essential general science topics in major competitive examinations.

Plane mirror propertiesConcave mirror applicationsMirror magnification formulaLight reflection lawsImage formation

Light and Mirrors Questions

Multiple choice evs magic with mirrors lateral inversion right or left reflection at plane surface

Two plane mirrors at an angle such that a ray incident on a mirror undergoes a total deviation of  $240 ^ { \circ }$ after two reflections. 

  1. the angle between the mirrors is $60 ^ { \circ }$

  2. the number of images formed by this system will be 5 , if an object is placed symmetrically between the mirrors.

  3. the no. of images will be 6 if an object is kept unsymmetrically between the mirrors.
  4. a ray will retrace its path after 2 successive reflections, if the angle of incidence on one mirror is $60 ^ { \circ }$ .
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The deviation produced by two mirrors inclined at angle theta is d = 360 - 2*theta. Given d = 240, 240 = 360 - 2*theta, so 2*theta = 120, theta = 60 degrees.

Multiple choice evs magic with mirrors lateral inversion right or left reflection at plane surface

Which of the following letters will be seen with some change in a plane mirror?

  1. M

  2. T

  3. L

  4. W
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Reflection through a plane mirror causes lateral inversion to the image.

The letters, M, T and W are laterally symmetric. So, no change will be observed after these letters are reflected on a plane mirror. The letter, L is not laterally symmetric. So, it will undergo lateral inversion and the image will appear different from the object.

Multiple choice evs magic with mirrors lateral inversion right or left reflection at plane surface

In the image formed by a plane mirror, the left of the object appears on the right and the right appears on the left. This is called lateral inversion.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Lateral inversion is a phenomenon in which the left side of object becomes right side of image and right side of object appears as left side of image.


Given statement is $True$.

Multiple choice evs magic with mirrors lateral inversion right or left reflection at plane surface

While standing in front of a plane mirror, if you touch your ............ ear with the  right hand, it will be seen in the mirror that your right ear is touched with your ................ hand.

  1. Right, left

  2. Left, left

  3. Right, right

  4. Left, right
Reveal answer Fill a bubble to check yourself
A,D Correct answer
Explanation

Right, Left or Left, Right both are correct,because thats the property of mirror.

Multiple choice conditions for a light ray to pass undeviated refraction of light at plane surfaces physics

A 5 cm thick glass slab is silvered at one of the surface to form a plane mirror. A point object is placed at a distance of $20cm $ from the unsilvered face. The image distance from the unsilvered face will be [R.I. of glass =1.5]

  1. 26.67cm
  2. $\frac {70}{3}$

  3. 20cm

  4. 25cm
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The object is at 20 cm from the unsilvered face. The light travels through 5 cm of glass (mu=1.5) to reach the mirror. The apparent distance of the object from the mirror is 5/1.5 + 20 = 3.33 + 20 = 23.33 cm. The mirror forms an image at 23.33 cm behind the mirror. The light then travels back through the glass, where the image appears at an apparent distance of 23.33 * 1.5 = 35 cm from the mirror surface. The total distance from the unsilvered face is 35 + 5 = 40 cm? Wait, recalculate: The mirror is at depth 5 cm. Object is at 20 cm from surface. Distance to mirror = 20 + 5/1.5 = 20 + 3.33 = 23.33. Image is at 23.33 behind mirror. Total distance from surface = 23.33 + 5/1.5 = 23.33 + 3.33 = 26.66 cm.

Multiple choice conditions for a light ray to pass undeviated refraction of light at plane surfaces physics

Which of the following statements is false?

  1. A plane mirror produce a magnification of +1

  2. Focal length of a plane mirror is infinite

  3. For man of height h, to see his own complete image , a mirror of height at least equal to h is required
  4. For a ray of light, incidenting normally on a plane mirror, the angle of reflection is $ 180^0 $
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

To see a full image in a plane mirror, the mirror height must be at least half the person's height (h/2), not equal to h. Thus, statement C is false.

Multiple choice physics reflection of light and shadow regular and irregular reflection regular and diffused reflection laws of reflection

Type of reflection in which images are formed and reflection occurs from a smooth surface like that of mirror is known as: 

  1. diffused reflection

  2. regular reflection

  3. irregular reflection

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

Regular reflection occurs from smooth surfaces and images are formed in this type of reflection.

Multiple choice physics reflection of light and shadow regular and irregular reflection regular and diffused reflection laws of reflection

When all the parallel rays reflected from a plane surface are parallel, the reflection is known as:

  1. regular reflection

  2. irregular reflection

  3. diffused reflection

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

When all the parallel rays reflected from a plane surface are parallel, the reflection is known as regular reflection .

Multiple choice physics reflection of light and shadow regular and irregular reflection regular and diffused reflection laws of reflection

Why we are not able to see our image on a cardboard even though it reflects light?

  1. Because cardboard does not shine like mirror

  2. Because cardboard is not as durable as mirror

  3. Because cardboard's surface is irregular

  4. All
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

We can"t see our image on a cardboard because cardboard"s surface is rough and the reflection occurring on uneven surface is irregular reflection. So, the rays, after reflection, move to different directions. Images are not formed due to irregular reflections.

Multiple choice physics motion and measurement measuring length measurement of small and large distances measurement of distance

Parallax is the apparent displacement of an object because of:

  1. change in observer's point of view

  2. change in object's position

  3. changes both in observers point of view and object's position

  4. consistency in observer's point of view
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Astronomers use an effect called parallax to measure distances to nearby stars. Parallax is the apparent displacement of an object because of a change in the observer's point of view.

As the Earth orbits the sun, a nearby star will appear to move against the more distant background stars. Astronomers can measure a star's position once, and then again 6 months later and calculate the apparent change in position.

Multiple choice physics motion and measurement measuring length measurement of small and large distances measurement of distance

To minimise parallax error, the observer should place the object :

  1. as near to the scale of the ruler as possible and the eye must be directly above the scale

  2. as far to the scale of the ruler as possible and the eye must be directly above the scale

  3. as near to the scale of the ruler as possible and the eye must be to the right of the scale

  4. as near to the scale of the ruler as possible and the eye must be to the left of the scale
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$Answer:-$ A

There are three simple ways of reducing parallax error in that case: 
1. Attach a straight object (like a ruler or straightened paperclip) to the thing you're measuring the displacement of, it should stick out of the object perpendicularly to the scale you're measuring the displacement on. 
2. Make sure that object is as close to your scale as possible, but not touching. 
3. Put your eyes level with the object, and as close to it as you safely can.

Multiple choice physics motion and measurement measuring length measurement of small and large distances measurement of distance

A student measure the height h of a convex mirror using spherometer. The legs of the spherometer are 4 cm apart and there are 10 divisions per cm on its linear scale and circular scale has 50 divisions. The student takes 2 as linear scale division and 40 as circular scale division. What is the radius of curvature of the convex mirror ?   

  1. $9.06 cm$
  2. $20.66 cm$
  3. $5.66 cm$
  4. $9.66 cm$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Least count of the spherometer is $LC=$ pitch/number of circular divisions $=\dfrac{1/10}{50}=0.002 cm$
The total reading for height is $h=MSR+(CSR\times LC)=(2\times 0.1)+(40\times 0.002)=0.28 cm$
The formula for radius of curvature is $R=\dfrac{l^2}{6h}+\dfrac{h}{2}=\dfrac{4^2}{6(0.28)}+\dfrac{0.28}{2}=9.66 cm$

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