Question

2. A CONVEX LENS HAVING RADIUS OF CURVATURE 30 CM
PRODUCED 3 TIMES ENLARGED REAL IMAGE. WHERE SHOULD
BE OBJECT PLACED.​

Answer 1

$\sf\small\red{Given:-}$

• The concave mirror produces three times enlarged image of an object placed at 10cm in front of it.

$\sf\small\red{Find:-}$

• We need to find out the focal length of the mirror.

$\sf\small\red{Solution:-}$

• As per the given conditions,
• m = 3 {A concave mirror produces three times enlarged image of an object and the }
• u = -10 cm

$\sf\small\red{Formula:-}$

We know that,

$m = \frac{u}{v}$

Substituting the known values we get,

3 = (-v)/(-10)

v = 30

The distance between the mirror and image = 30 cm

From mirror formula, we know

(-2)/30 = 1/f

or f = – 15

The radius of curvature R = 2f

∴ R = 2 × (- 15)

R = -30 cm.