A thin prism of angle 15⁰ made of glass of refractive index µ₁ = 1.5 is combined with another prism of glass of refractive index µ₂ = 1.75. The combination of the prism produces dispersion […]
When an object is placed 40cm from a diverging lens, its virtual image is formed 20 cm from the lens. The focal length and power of lens are
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(a) F=-20 cm, P=-5 D […]
Which one of the following is not due to total internal reflection?
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(a) working of optical fibre (b) Difference between apparent and real depth of pond (c) Mirage on hot summer days […]
An object is 8 cm high. It is desired to form a real image 4 cm high at 60 cm from the mirror. The type of mirror needed with the focal length is
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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:
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(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
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(a) […]
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