Question

find the radii of curvature of a concavo-convex convergent lens made of glasses with the refractive index n=1.5 having focal length of 20% of the radii of curvature is double the other​

Answer 1

Answer:

Given: a convexo-concave convergent lens made of pf glass with refractive index, ν=1.5 and focal length, f=24cm. It has one of the radii of curvature is double the other

To find its radii of the curvature

Solution:

According to the given criteria,

R

1

=2R

2

for convexo-concave lens R

1

is positive and R

2

is positive

According to the lens maker formula,

f

1

=(n−1)(

R

1

1

−

R

2

1

)

⟹

24

1

=(1.5−1)(

R

1

1

−

2R

1

1

)

⟹

24×0.5

1

=

2R

1

2−1

⟹R

1

=

2

12

=6cm

∴,R

2

=2R

1

=12cm

Hence the radii of the curvature is 6cm and 12cm

Answer 2

Answer:

it is a fair answer

Explanation:

Given: a convexo-concave convergent lens made of pf glass with refractive index, ν=1.5 and focal length, f=24cm. It has one of the radii of curvature is double the other

To find its radii of the curvature

Solution:

According to the given criteria,

R

1

=2R

2

for convexo-concave lens R

1

is positive and R

2

is positive

According to the lens maker formula,

f

1

=(n−1)(

R

1

1

−

R

2

1

)

⟹

24

1

=(1.5−1)(

R

1

1

−

2R

1

1

)

⟹

24×0.5

1

=

2R

1

2−1

⟹R

1

=

2

12

=6cm

∴,R

2

=2R

1

=12cm

Hence the radii of the curvature is 6cm and 12cm