Question

13. radius of curvature of a
convex lens is 10 cm then its
focal length is
O 5cm
O 10cm
O 15cm
O 20cm​

Answer 1

Answer:

5 cm.

Explanation:

Given :-

Radius of curvature (R) = 10 cm

To find :-

Focal length (F)

Solution :-

➔ R = 2F

➔ 10 = 2(F)

➔ F = 10/2

➔ F = 5

∴ Focal length of the lens is 5 cm.

Answer 2

Answer:-

• Radius of the Culvature=R=10cm
• Focal length=f=?

We know that

$\boxed{\sf R=2f}$

$\\ \rm\longmapsto f=\dfrac{R}{2}$

$\\ \rm\longmapsto f=\dfrac{10}{2}$

$\\ \rm\longmapsto f=5cm$

• Focal length of the convex lens is 5cm.

Hence option a is correct

●5cm

○10cm

○15cm

○20cm