Question

A ray of light falls on a plane mirror. When the mirror is turned, about an axis at right angle to the plane of the mirror through 20o, the angle between the incident ray and new reflected ray is 45o. The angle between the incident ray and original reflected ray is

Solution

Correct option is

45o

When mirror rotated through an angle θ about an axis in the plane of mirror then reflection ray rotated through an angle 2θ perpendicular to the plane of mirror the angle of incidence and angle of reflection does not change.

SIMILAR QUESTIONS

Q1

The largest wavelength in the ultraviolet region of the hydrogen spectrum is 122nm. The smallest wavelength in the infrared region of the hydrogen spectrum (To the nearest integer)is:

Q2

A point source S is centered in front of a 70 cm wide plane mirror. A man starts walking from the source along a line parallel to the mirror at a distance 2L from it.

Q3

 

The size of the face of a dancer is 24 cm ×16 cm. The minimum size of a plane mirror required to see the face of dancer completely by 

(i) one eyed dancer.        (ii) two eyed dancer  

(Distance between the eyes is 4 cm)

Q4

A fluorescent lamp of length 1 m is placed horizontal at a depth of 1.2 m below a ceiling. A plane mirror of length 0.6 m is placed below the lamp parallel to and symmetric to the lamp at a distance 2.4 m from it. The length of the reflected patch of light on the ceiling is

Q5

Two plane mirrors are placed parallel to each other. A point object is placed between them. The distance of image formed in one of the mirror is in

                                                                                                 

Q6

 

Two plane mirrors are parallel to each other and spaced 20 cm apart. A luminous point object is placed between them and 5 cm from one mirror. What are the distances from each mirror of the three nearest images in each?    

 
Q7

If two adjacent walls and the ceiling of a rectangular room are mirror surfaced, then how many images of himself, a man can see?

 

Q8

 

Two bodies A and B are moving towards a plane with speeds VA and VB respectively as shown in figure. The speed of image of A with respect to the body B is

                                                                                                  

Q9

A beam of convergent light converges to a point 0.5 in front of the mirror after reflection at a convex mirror but in the absence of the mirror the beam converges to a point 0.2 behind the mirror. The radius of curvature of the mirrors is

                                                                              

Q10

A particle executes SHM in front of a concave mirror of radius 1 m, about the centre of curvature, with very small amplitude a. The amplitude of oscillation of the image is