An object 2.5 cm high is placed at a distance of 10 cm from a concave mirror of radius of curvature 30 cm. The size of the image is

Question

An object 2.5 cm high is placed at a distance of 10 cm from a concave mirror of radius of curvature 30 cm. The size of the image is (A) 9.2 cm (B) 10.5 cm (C) 5.6 cm (D) 7.5 cm

Tardigrade Admin · Accepted Answer

R=-30 cm ⇒ f=-15 cm , O=+2.5 cm , u=-10 cm By mirror formula (1/-15)=(1/v)+(1/(-10)) ⇒ v=30 cm Also (I/O)=-(v/u) ⇒ (1/(+2.5))=(30/(-10)) ⇒ I=+7.5 cm

Q. An object $2.5 c m$ high is placed at a distance of $10 c m$ from a concave mirror of radius of curvature $30 c m$ . The size of the image is

9.2 cm

10.5 cm

5.6 cm

7.5 cm

$R = - 30 c m$
$\Rightarrow f = - 15 c m, O = + 2.5 c m, u = - 10 c m$
By mirror formula $\frac{1}{- 15} = \frac{1}{v} + \frac{1}{( - 10 )}$
$\Rightarrow v = 30 c m$
Also $\frac{I}{O} = - \frac{v}{u}$
$\Rightarrow \frac{1}{( + 2.5 )} = \frac{30}{( - 10 )}$
$\Rightarrow I = + 7.5 c m$

Q. An object 2.5cm high is placed at a distance of 10cm from a concave mirror of radius of curvature 30cm. The size of the image is