Physics Ray Optics and Optical Instruments

A fish looking up through the water sees the outside world contained in a circular horizon. If the refractive index of water is $4/3$ and the fish is 12cm  below the surface of water, the radius of the circle in centimeter is:

A telescope with objective of focal length  $100cm$ and eyepiece of focal length $5cm$ is focused on a far object such that parallel rays emerge from eyepiece. If object subtends an angle of $1^0$  on objective, the angular size of image is

Deviation of light ray by a thin prism of refractive index $\mu$ and refracting angle $A$  is

A farsighted person cannot focus distinctly objects closer than 100cm. The lens that will permit him to read from a distance of 50cm, will have a focal length:

A point source of light S, placed at a distance 60cm infront of the centre of a plane mirror of width 50cm, hangs vertically on a wall. A man walks inform of the mirror along a line parallel to the mirror at a distance 1.2m from it (see in the figure). The distance between the extreme points where he can the image of the light source in the mirror is………….cm.

Given below are two statements : one is labeled as Assertion A and the other is labeled as Reason R.

Assertion A : For a simple microscope, the angular size of the object equals the angular size of the image.

Reason R : Magnification is achieved as the small object can be kept much closer to the eye that 25cm and hence it subtends a large angle.

In the light of the above statements, choose the most appropriate answer from the options given below:

The incident ray, reflected ray and the outward drawn normal are denoted by the unit vectors $\overrightarrow{a},\overrightarrow{b}and\overrightarrow{c}$  respectively. Then choose the correct relation for these vectors.

A light ray is incident, at an incident angle q₁, on the system of two plane mirrors M₁ and M₂ having an inclination angle 75° between them (as shown in figure). After reflecting from mirror M₁ it gets reflected back by the mirror M₂ with an angle of reflection 30°. The total deviation of the ray will be ___________ degree.

 

The speed of light in media 'A' and 'B' are 2.0 * 10¹⁰ cm/s and 1.5 * 10¹⁰ cm/s respectively. A ray of light enters from the medium B to an incident angle 'q'. If the ray suffers total internal reflection, then

The aperture of the objective is 24.4 cm. The resolving power of this telescope, if a alight of wavelength 2440 $\stackrel{o}{A}$  is used to see the object will be: