Question

An object is kept 10cm in front of a convex mirror which forms a smaller image three fifths the size of the object

Answer 1

Explanation:

given:- u = -10 cm

let the height of the object be x.

then, height of image be 3x/5

we know, m = -v/u = height of image/ height of objects

therefore, -v/u= h'/h

-v/-10= 3x/5/ x = 3x/5x

-v/-10= 3x/5x

-v/-10= 3/5

v= 3 × 10 / 5

v = 3×2 = 6

v= 6cm

we know, using mirror formula

1 / f = 1/v + 1/u

1/f = 1/6 + 1/ -10

= 1/6 - 1/ 10

=

_5-3__

30

= 2/30 = 1 / 15

f= 15cm