An object of height h=5cm is located at a distance a=12cm from a concave mirror with focal length 10cm. Then height of image:-

Question

An object of height h=5cm is located at a distance a=12cm from a concave mirror with focal length 10cm. Then height of image:- (A) 10cm (B) 15cm (C) 20cm (D) 25cm

Tardigrade Admin · Accepted Answer

(1/v)+(1/u)=(1/f) v=(u f/u - f)=((- 12) (- 10)/- 12 - (- 10))=-60cm (hi/5)=-(v/u)⇒ (hi/5)=-((- 60/- 12))⇒ hi=-25cm

Q. An object of height $h = 5 c m$ is located at a distance $a = 12 c m$ from a concave mirror with focal length $10 c m .$ Then height of image:-

$10 c m$

$15 c m$

$20 c m$

$25 c m$

$\frac{1}{v} + \frac{1}{u} = \frac{1}{f}$
$v = \frac{u f}{u - f} = \frac{( - 12 ) ( - 10 )}{- 12 - ( - 10 )} = - 60 c m$
$\frac{h _{i}}{5} = - \frac{v}{u} \Rightarrow \frac{h _{i}}{5} = - (\frac{- 60}{- 12}) \Rightarrow h_{i} = - 25 c m$

Q. An object of height h=5cm is located at a distance a=12cm from a concave mirror with focal length 10cm. Then height of image:-

10cm

15cm

20cm

25cm