Question

Focal length of the convex lens in 20cm and refractive index is 1.5 what is the focal length when it is dipped in liquid of refractive infex of 1.33​

Answer 1

Answer:

From lens maker's formula,

f

1

=(μ−1)(

R

1

1

−

R

2

1

)

20

1

=(1.5−1)(

R

1

−

(−2R)

1

)

20

1

=

2

1

×

2R

3

R=15cm

∴ length of radius =(2R)=2×15 cm=30 cm