Question

37. The radii of curvatures of convex lens are 24cm and 8cm. Its refractive
index is 1.5, then its focal length is
a) 8cm
b) 12cm
c) 16cm d) 4cm
​

Answer 1

Answer:

From Lens makers formula, f1=(μ−1)(R11−R21)

R1=∞

R2=−20 cm

f1=(1.5−1)(201)

f=40cm