physics ncert exemplar solution class 12th chapter one

Three light waves combine at a certain point, where their electric field components are  E₁ =E₂

Find their resultant component E(t) at that point:

A small coin is resting on the bottom of a beaker filled with liquid. A ray of light from the coin travels upto the surface of the liquid and moves along its surface. How fast is the light travelling in the liquid?

An object of height 1.5cm is placed on the axis of a convex lens of focal length 25cm. A real image is formed at a distance of 75cm from the lens. The size of the image will be

A circular beam of light of diameter d=2cm falls on a plane surface of glass. The angle of incidence is 60⁰ and refractive index of glass is $\mu =3/2$ . The diameter of the refracted beam is:

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:

An alternating potential V=V₀ sin wt is applied across a circuit. As a result the current I=I₀ Sin $I=I_0 sin \left(\omega t-\frac{\pi }{2}\right)$  flows in it. The power consumed in the circuit per cycle is

The current in an inductor is given by $i=2+3t$  ampere where t is in second. The self?induced emf in it is $9 mV$ ; the energy stored in the inductor at t=1 second is

A current 1 flows along the length of an infinitely long, straight and thin?walled pipe. Then:

Two long conductors, separated by a distance d carry current $I_1$ and $I_2$ in the same direction. They exert a force F on each other. Now the current in one of them is increased to two times and its directions is reversed. The distance is also increased to 3 d. The new value of the force between them is

A neutral point is obtained at the Centre of a vertical circular coil carrying current. The angle between the plane of the coil and the magnetic meridian is