A ray of light travelling in a transparent medium of refractive index µ, falls on surface seperating the medium from air at an angle of incidence of 45⁰. For which of the following value of […]
For a normal eye, the cornea of eye provides a converging power 40 D and the least converging power of the eye lens behind the cornea is 20 D. Using this information, the distance between […]
A boy is trying to start a fire by focusing sunlight on a piece of paper using an equiconvex lens of focal length 10 cm. The diameter of the sun is 1.39 x 10⁹ m […]
Two thin lenses of focal lengths f₁ and f₂ are in contact and coaxial. The power of the combination is:
Options
(a) √ f₁ / f₂ (b) √ f₂ / f₁ (c) f₁ […]
Diameter of the objective of a telescope is 200 cm. What is the resolving power of a telescope? Take wavelength of light=5000Å.
Options
(a) 6.56×10⁶ (b) 3.28×10⁵ (c) 1×10⁶ (d) 3.28×10⁶
Correct Answer:
3.28×10⁶
An astronomical telescope arranged for normal adjustment has a magnification of 6. If the length of the telescope is 35 cm, then the focal lengths of objective and eye-piece rspectively, are
Options
(a) […]
The intermediate image formed by the objective of a compound microscope is
Options
(a) real, inverted and magnified (b) real, erect and magnified (c) virtual, erect and magnified (d) virtual, inverted and magnified
Correct […]
Astigmatism is corrected by using
Options
(a) cylindrical lens (b) plano-convex lens (c) plano-concave lens (d) convex lens
Correct Answer:
cylindrical lens
Explanation:
In this defect, eye cannot perpendicular directions clearly that is horizontal […]
A focal length of a lens is 10 cm. What is power of a lens in dioptre?
Options
(a) 0.1 D (b) 10 D (c) 15 D (d) 1 D
Correct Answer:
10 […]
A luminous object is seperated from a screen by distance d. A convex lens is placed between the object and the screen such that it forms a distinct image on the screen. The maximum possible […]
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