Question

Two identical point particles A and B are placed in front of a concave mirror of focal length 20 cm, at distances 10 cm and 30 cm respectively. The particles oscillate perpendicular to the principal axis, such that the displacement equation for both the particles is given by. The correct statement (s) is/are

Answer 1

Given:

Two identical point particles A and B are placed in front of a concave mirror of focal length 20 cm, at distances 10 cm and 30 cm respectively. The particles oscillate perpendicular to the principal axis, such that the displacement equation for both the particles is given by.  

To find:

The correct statement (s) is/are

Solution:

From given, we have,

The focal length of a concave mirror = f = 20 cm

A particle A is placed at a distance = uA = 10 cm

A particle B is placed at a distance = uB = 30 cm

we use the magnification formula,

u = f (1 + 1/m)

mA/mB = (uB - f)/(uA - f)

= (30 - 20)/(10 - 20)

= 10/(-10)

= -1

Therefore, mA/mB = -1

The image of particle A is the same as that of the image of particle B.