Physics NCERT Exemplar Solutions Class 12th Chapter Eight

The magnetic field of a plane electromagnetic wave is given by:

$\overrightarrow{B}=2*10^{-8}$ sin(0.5 * 10³x + 1.5 * 10¹¹t) $\widehat{j}$ T.

The amplitude of the electric field would be:

A tuning fork A of unknown frequency produces 5 beats/s with a fork of known frequency 340 Hz. When fork A is filed, the beat frequency decreases to 2 beats/s. What is the frequency of fork A?

Sun light falls normally on a surface of area 36cm² and exerts an average force of 7.2 * 10^-9N within a time period of 20 minutes. Considering a case of complete adsorption, the energy flux of incident light is

Choose the correct option relating wavelengths of different parts of electromagnetic wave spectrum:

On the $x$ -axis and at a distance $x$ from the origin, the gravitational field due to a mass distribution is given by $\frac{Ax}{{\left(x^2+a^2\right)}^{3/2}}$ in the $x$ -direction. The magnitude of gravitational potential on the $x$ -axis at a distance $x$ , taking its value to be zero at infinity is:

On the $x$ -axis and at a distance $x$ from the origin, the gravitational field due to a mass distribution is given by $\frac{Ax}{{\left(x^2+a^2\right)}^{3/2}}$ in the $x$ -direction. The magnitude of gravitational potential on the $x$ -axis at a distance $x$ , taking its value to be zero at infinity is:

A radar sends an electromagnetic single of electric (E₀) = 2.25 V/m  and magnetic field (B₀) = 1.5 * 10^-8 T which strikes a target on line of sight at a distance of 3km in a medium. After that, a part of signal (echo) reflects back towards the radar with same velocity and by same path. If the signal was transmitted at time t = 0  from radar, then after how much time echo will reach to the radar?

Two planets A and B of equal mass are having their period of revolutions T_A and T_B such that T_A = 2T_B. These planets are revolving in the circular orbits or radii r_A and r_B respectively. Which out of the following would be the correct relationship of their orbits?

If the acceleration due to gravity experienced by a point mass at a height h above the surface of earth is same as that of the acceleration due to gravity at a dept ah(h <e) from the earth surface. The value of a will be_______.

Match List – I with List – II:

List – I List – II

(A) UV rays (i) Diagnostic tool in medicine

(B) X-rays(ii) Water purification

(C) Microwave(iii) Communication, Radar

(D) Infrared wave(iv) Improving visibility in foggy daya

Choose the correct answer from the options given below: