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 kaleidoscope uses of plane mirror reflected light can be reflected again

An object is kept between two plane mirrors inclined at an angle $120$ from each other; calculate the number of images which are formed if the object is not on the bisector/on the bisector $3$

  1. $\displaystyle \frac {3}{3}$
  2. $\displaystyle \frac {3}{2}$
  3. $\displaystyle \frac {2}{2}$
  4. $\displaystyle \frac {2}{3}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Given: An object is kept between two plane mirrors inclined at an angle 120 from each other

To find the ratio of number of images which are formed if the object is not on the bisector and on the bisector
Solution:
If there are two plane mirrors inclined to each other at an angle $\theta$, the number of images of a point object formed are determined as follows:

If $\left(\dfrac {360^\circ}\theta\right)$ is odd integer (say $m$) number of images formed
$n = m$, if the object is not on the bisector of mirrors
$n = (m – 1)$, if the object is on the bisector of mirrors.

So, when $\theta=120^\circ$, we get
$m=\dfrac {360}{120}=3$
So,
$\dfrac {\text{ number of images which are formed if the object is not on the bisector}}{\text{ number of images which are formed if the object is on the bisector}}=\dfrac {3}{3-1}=\dfrac 32$

Multiple choice maths does it look the same? reflection on coordinate axis reflection w.r.t a line reflection

When an object is reflected in the mirror, the corresponding lengths and angles of the object and the image

  1. remain same

  2. increase in the image

  3. decrease in the image

  4. cannot be determined
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When an object is reflected, there is no change in the lengths and angles; i.e. the lengths and angles of the object and the corresponding lengths and angles of the image are the same. However, in one aspect there is a change, i.e. there is a difference between the object and the image. The left and the right sides of an object appear inverted in a mirror
hence option A is correct

Multiple choice maths does it look the same? reflection on coordinate axis reflection w.r.t a line reflection

A circle with centre $(0,0)$ and of radius $2$ cm is plotted in the XY plane. Take the part of circle in first quadrant and find its reflection through X axis.

  1. The reflected image will form in $3rd$ quadrant.
  2. The reflected image will form in $1st$ quadrant.
  3. The reflected image will form in $2nd$ quadrant.
  4. The reflected image will form in $4rth$ quadrant.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
The graph is symmetric(reflection) w.r.t to the $x$-axis i.e. $y=0$ , If $(x,y)$ is a point on the graph ,then $(x,-y)$ is also a point on the graph .

in first quadrant both $x$ and $y$ are positive ,
using above concept ,all the point of circle which lie on the first quadrant has a reflection about $X$-axis at $(x,-y)$ .

And we know points $(x,-y)$ always lie in $4^{th}$ quadrant .
Multiple choice maths does it look the same? reflection on coordinate axis reflection w.r.t a line reflection

A circle with centre $(0,0)$ and of radius $2$ cm is plotted in the XY plane. Take the part of circle in first quadrant and find its reflection through Y axis.

  1. The reflected image would get formed in $1st$ quadrant.
  2. The reflected image would get formed in $2nd$ quadrant.
  3. The reflected image would get formed in $4rth$ quadrant.

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
The graph is symmetric (reflection) w.r.t to the $y$-axis i.e. $x=0$ , If $(x,y)$ is a point on the graph ,then $(-x,y)$ is also a point on the graph .

As we know points $(x,y)$ lie at $1^{st}$ quadrant --------   (both $x$ and $y$ are positive ).
Using above concept , all the reflected points of first quadrant about $Y$-axis lie at $(-x,y)$.
And we know points $(-x,y)$ lie in $2^{nd}$ quadrant .

Multiple choice maths does it look the same? reflection on coordinate axis reflection w.r.t a line reflection

 Line symmetry and mirror reflection are naturally related to each other.

  1. True

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

A figure may have both horizontal and vertical lines of reflection.An object and its images are always at the same distance from the surface of a mirror, which is called the mirror line. Line symmetry and mirror reflection are naturally related and linked to each other. So, the option is true.

Multiple choice maths does it look the same? reflection on coordinate axis reflection w.r.t a line reflection

The distance of the object from the mirror line is ____ the distance of the image from the mirror line.

  1. same as

  2. greater than

  3. less than

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

An objects and its image are always at the same distance from the surface of mirror,  which is called the mirror line. Therefore the distance of the object from the mirror line is same as the distance of the image from the mirror line

Multiple choice physics reflection of light and shadow lateral inversion right or left reflection at plane surface

Mark correct option.

  1. The laws of reflection of light hold only for plane surfaces

  2. The size of virtual image can be measured by receiving it on screen

  3. Plane mirror alongs form an erect image

  4. Plane mirror may form inverted image
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let solve it by each option

  1. Law of reflection of light holds good for all the mirrors irrespective of their shape and size, hence option A is false
  2.  A virtual image cannot be caught on screen so we cannot measure the size, it is also a false statement
  3. Plane mirror always forms a virtual image, hence it's a false statement
  4. Light rays  which comes from the object  get reflected from plane mirror and reaches to human eye, at this point human feel that reflected ray is coming from the mirror . This is the reason why object looks laterally inverted
  5. Hence option D is the right answer

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

Lateral inversion is a feature of plane mirrors, in which:

  1. The top part of the object appears to be the bottom part of the image.

  2. The left side of the object appears to be the right side of the image.

  3. Image appears to be inverted upside down and also sideways.

  4. All of the above.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
$ \bf{Lateral\ Inversion} $ is the phenomenon in which when looked through a mirror, the left-hand side of an object appears as right-hand side of the image and vice versa.

Hence, the correct answer is OPTION B.
Multiple choice evs magic with mirrors lateral inversion right or left reflection at plane surface

Why is it difficult to read from image of a book in plane mirror?

  1. Due to lateral inversion

  2. Due to scattering

  3. Due to vertical inversion

  4. Due to loss on reflection
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

On reflection, Objects undergo lateral inversion.

Most of the alphabets are not symmetrical laterally and on reflection produce unrecognizable alphabets. Also, letters on the right appear on the left. This hurt the sequence of letters and makes words and sentences meaningless.

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

Interchange of left and right sides of an object in a plane mirror is known as:

  1. reflection

  2. refraction

  3. lateral inversion

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

The interchange of the left and right sides in the image of the object in a plane mirror is known as lateral inversion. In our daily experience, while looking in a mirror, the pocket of the left appears to be on the right of the image is also an example of lateral inversion.