Question

22. An object of height 4 cm is placed at 15 cm in front of a concave mirror of focal length
10 cm. At what distance from the mirror should a screen be placed to obtain a sharp
image of the object. Calculate the height of image.​

Answer 1

Answer:

H=4cm. Explanation:height of object

U=15cm distanceofobject and mirror

F= -10 cm

H' and V we have to find,

1/F = 1/U + 1/V

1/v = 1/f - 1/u => 1/-10 - 1/-15

= 1/-10 + 1/15 = -3+2/30.

(L.C.M.is30)

1/v= -1/30

Therefore, v = -30cm

M= H'/H = -V/U

= H' = -v*H/U = -(-30)*4/-10

= H' = 30*4/-10= 3*4/-1

= H' = 12/-1 = -12CM

WHICH MEANS image is inverted ,in front of the mirror and virtual and erect