A double convex lens has radii 20 cm. The index of refraction of glass is 1.5. Compute the focal length of this lens in air and when immersed in carbon disulphide of refractive index 1.63.
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An eye-piece consists of a concave lens of focal length 2f and a convex lens of focal length 3f separted by a distance `(f)/(2)`. They are of the same
Correct Answer - Free from chromatic aberration but not spherical, yes
2 Answers 1 views
An achromatic objective of focal length 1.5m is to be constructed with a crown glass convex lens `(mu=1.51, omega=0.21)` and a flint glass concave len
Correct Answer - 0.18m (convergent)
2 Answers 1 views
The redius of curvature of the convex face of a plano-convex lens is 12cm and its refractive index is 1.5. a. Find the focal length of this lens. The
Correct Answer - (a) `+24 cm`; (b) `- 36cm` (c) `12 cm`(d) `- 180 cm`
2 Answers 1 views
A convex lens of focal length `15 cm` is placed in front of a convex mirror. Both are coaxial and the lens is `5 cm` from the apex of the mirror. When
Correct Answer - 55 cm
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The focal length of a concave-convex lens of radii of curvature 5 cm and 10 cm is 20 cm. what will be its focal length in water ? Given `.^(a)mu_(w) =
Correct Answer - `-80 cm`
2 Answers 2 views
A convex lens of refractive index 1.5 is immersed in a liquid of refractive index (i) 1.6 (ii) 1.3 and (iii) 1.5. what changes happens to the focal le
Correct Answer - (i) - 8f (ii) `+3.25f` (iii) `oo`
2 Answers 1 views
The focal length of a plano-convex lens is 20 cm in air. Refractive index of glass is 1.5. Calculate (i) the radius of curvature of lens surface and (
Correct Answer - (i) `-10 cm` (ii) `-160 cm`
2 Answers 2 views
A compound lens has been formed by joinined a convex and a concave lens, each of focal length 30 cm. what is the focal length of the combination? What
Correct Answer - Infinite, zero
2 Answers 1 views
Find the focal length and power of a convex lens, which when placed in contact with a concave lens of focal length `25 cm` forms a real image `5` time
Correct Answer - 10 cm, 10D
2 Answers 1 views
The power of a thin convex lens of glass is `5 dioptre`. When it is immersed in a liquid of refractive index `mu`, it behave like a diverging lens of
Correct Answer - `5//3`
2 Answers 1 views