Question

An object is 17.7 cm away from a concave mirror with focal length 14.2 cm.

(a) Find the image distance, q.
cm

(b) Find its magnification.


(c) State whether the image is real or virtual.

real

virtual     

(d) State whether the image is upright or inverted.

upright

inverted    

I WILL RATE

Answer 1

Solution: a) Using thin lens equation: 1/f = 1/p + 1/q

Where, q is the distance of the image from mirror.

f - focal length = -14.2 cm (given) [ Focal length of a concave lens is to be considered negative in the equation]

p - distance of the object from the mirror = 17.7 cm.

=. 1/-14.2 = 1/v + 1/17.7

=> q = - 7.87 cm. Answer

b) Thus, Magnification = -q/p = 7.87 / 17.7 = 0.444 Answer

c) As, q is negative which means the image produced is virtual. Answer

d) The image produced by concave lens is always upright. Answer