Thin Lens Formula and Lens Maker Formula NEET Questions

Physics - Optics

Thin Lens Formula and Lens Maker Formula MCQ Questions


1.
The thin lens formula is given by:
A.
1/v - 1/u = 1/f
B.
1/u - 1/v = 1/f
C.
1/v + 1/u = 1/f
D.
v - u = f
😑 View Answer Rough Work Error
ANSWER :
A. 1/v - 1/u = 1/f
2.
The thin lens formula is valid for:
A.
Only convex lenses with real images
B.
Both convex and concave lenses, for both real and virtual images
C.
Only concave lenses
D.
Only paraxial rays from a point source on axis
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ANSWER :
B. Both convex and concave lenses, for both real and virtual images
3.
In the lens formula 1/v - 1/u = 1/f, the sign convention takes:
A.
Image distance v always negative
B.
Object distance u always positive
C.
All distances from the optical centre as positive
D.
Distances measured along the direction of incident light as positive, against it as negative
😑 View Answer Rough Work Error
ANSWER :
D. Distances measured along the direction of incident light as positive, against it as negative
4.
For a real object placed in front of a convex lens, the object distance u is:
A.
Always equal to focal length
B.
Positive
C.
Zero
D.
Negative
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ANSWER :
D. Negative
5.
The lens maker's formula for a thin lens in air is:
A.
1/f = n(1/R₁ - 1/R₂)
B.
1/f = (n + 1)(1/R₁ + 1/R₂)
C.
1/f = (n - 1)(1/R₁ - 1/R₂)
D.
1/f = (n - 1)(1/R₁ + 1/R₂)
😑 View Answer Rough Work Error
ANSWER :
C. 1/f = (n - 1)(1/R₁ - 1/R₂)
6.
The lens maker's formula when the lens (refractive index n₂) is placed in a medium of refractive index n₁ is:
A.
1/f = (n₁ - n₂)(1/R₁ + 1/R₂)
B.
1/f = (n₁/n₂ - 1)(1/R₁ - 1/R₂)
C.
1/f = (n₂/n₁ - 1)(1/R₁ - 1/R₂)
D.
1/f = (n₂ - n₁)(1/R₁ - 1/R₂)
😑 View Answer Rough Work Error
ANSWER :
C. 1/f = (n₂/n₁ - 1)(1/R₁ - 1/R₂)