84
You visited us
84
times! Enjoying our articles?
Unlock Full Access!
Byju's Answer
Standard XII
Physics
Lens Maker's Formula
What is the f...
Question
What is the focal length of double concave lens kept in air with two spherical surface of radii
R
1
=
30
c
m
and
R
2
=
60
c
m
. Take refractive index of lens as
μ
=
1.5
.
Open in App
Solution
Using lens makers formula
1
f
=
(
μ
−
1
)
[
1
R
1
−
1
R
2
]
where
R
1
=
−
v
e
1
f
=
(
1.5
−
1
)
[
1
(
−
30
)
−
1
60
]
1
f
=
(
0.5
)
[
3
60
]
=
−
0.5
×
1
20
f
=
−
40
c
m
Suggest Corrections
3
Similar questions
Q.
What is the focal length of a double convex lens kept in air with two spherical surfaces of radii
R
1
=
30
c
m
and
R
2
=
60
c
m
?
(Take the refractive index of the lens as
1.5
).
Q.
What is the focal length of double concave lens kept in air with two spherical surfaces of radii
R
1
=
−
20
c
m
and
R
2
=
80
c
m
. Take refractive index of lens with respect to surrounding as n = 1.5.
Q.
The radii of curvature of a double concave lens are
30
c
m
and
60
c
m
and the refractive index of its glass is
1.5
. Calculate the focal length of the lens.
Q.
Focal length of equiconvex lens with radius of each surface being
30
c
m
and refractive index
1.5
, is
Q.
Arrange the following data according to the increasing order of its focal length of given double covex lens of radius of curvature of the curved surfaces and corresponding refractive index of the material
a)
R
1
=
R
2
=
2
c
m
μ
=
1.5
b)
R
1
=
20
c
m
,
R
2
=
10
c
m
μ
=
1.6
c)
R
1
=
20
c
m
,
R
2
=
30
c
m
μ
=
1.5
d)
R
1
=
20
c
m
,
R
2
=
40
c
m
μ
=
1.5
View More
Join BYJU'S Learning Program
Grade/Exam
1st Grade
2nd Grade
3rd Grade
4th Grade
5th Grade
6th grade
7th grade
8th Grade
9th Grade
10th Grade
11th Grade
12th Grade
Submit
Related Videos
Thin Lenses: Point Objects
PHYSICS
Watch in App
Explore more
Lens Maker's Formula
Standard XII Physics
Join BYJU'S Learning Program
Grade/Exam
1st Grade
2nd Grade
3rd Grade
4th Grade
5th Grade
6th grade
7th grade
8th Grade
9th Grade
10th Grade
11th Grade
12th Grade
Submit
Solve
Textbooks
Question Papers
Install app