List of top Physics Questions on Optical Instruments

In a microscope of tube length $10\,\text{cm}$ two convex lenses are arranged with focal lengths $2\,\text{cm}$ and $5\,\text{cm}$. Total magnification obtained with this system for normal adjustment is $(5)^k$. The value of $k$ is ___.
There is a compound microscope of lenses having focal lengths 2 cm and 5 cm and tube length 10 cm. Find magnifying power in normal adjustment. If your answer is $5^\alpha$, find '$\alpha$' :
A microscope has an objective of focal length \(f_o = 2\) cm and an eyepiece of focal length \(f_e = 4\) cm. The tube length of the microscope is \(L = 40\) cm. If the distance of distinct vision of eye is \(D = 25\) cm, the magnification in the microscope is:
A concave mirror has a focal length of 20 cm. An object is placed 60 cm in front of the mirror. Find the image distance.
The clarity of the image formed on the retina of the eye depends on the ____
In normal adjustment, for a refracting telescope, the distance between the objective and eyepiece lens is 1.00 m. If the magnifying power of the telescope is 19, find the focal length of the objective and the eyepiece lens.
Two different lenses are used in telescope because
A scientist is observing a bacteria through a compound microscope. For better analysis and to improve its resolving power he should. (Select the best option)
Only 2% of the optical source frequency is the available channel bandwidth for an optical communicating system operating at 1000 nm. If an audio signal requires a bandwidth of 8 kHz, how many channels can be accommodated for transmission?
A telescope has an objective lens of 10 cm diameter and is situated at a distance of one kilometer from two objects. The minimum distance between these two objects which can be resolved by the telescope, when the wavelength of light is 5000AA, is of the order of
The magnifying power of a telescope is 9. When it is adjusted for parallel rays, the distance between the objective and the eye piece is found to be 20 cm. The focal length of lenses are:
Resolving power of a telescope will be more, if the diameter of the objective is:

The two surfaces of a biconvex lens are of radius of curvature \( R \) each. Obtain the condition under which its focal length \( f \) is equal to \( R \). If one of the two surfaces of this lens is made plane, what will be the new focal length of the lens?