A lens of large focal length and large aperture is best suited as an objective of an astronomical telescope since:
Held on 30 Apr 2021 · Verified 9 Jul 2026.
a large aperture contributes to the quality and visibility of the images.
a large area of the objective ensures better light gathering power.
a large aperture provides a better resolution.
all of the above.
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The refractive index of glass is 1.5. The speed of light in glass is:
Two thin lenses of focal lengths f₁ = +20 cm and f₂ = -10 cm are in contact. The power of the combination is:
In a certain camera, a combination of four similar thin convex lenses are arranged axially in contact. Then the power of the combination and the total magnification in comparison to the power $(p)$ and magnification $(m)$ for each lens will be, respectively
The intensity of transmitted light when a polaroid sheet, placed between two crossed polaroids at $22.5^{\circ}$ from the polarization axis of one of the polaroid, is ( $\mathrm{I}_0$ is the intensity of polarised light after passing through the first polaroid):
A microscope has an objective of focal length 2 cm , eyepiece of focal length 4 cm and the tube length of 40 cm . If the distance of distinct vision of eye is 25 cm , the magnification in the microscope is :
Work through every NEET UG Optics PYQ, year by year.