Electromagnetic Waves — Physics STD 12 Science — Question

1. Explain the formation of depletion layer and potential barrier in a p-n junction.
2. In the figure given below the input waveform is converted into the output waveform by a device ‘X’. Name the device and draw its circuit diagram.

3. Identify the logic gate represented by the circuit as shown and write its truth table.

Clear the difference between interference and diffraction.

An electron gun with its collector at a potential of 100 V fires out electrons in a spherical bulb containing hydrogen gas at low pressure (∼10^–2 mm of Hg). A magnetic field of 2.83 × 10^–4 T curves the path of the electrons in a circular orbit of radius 12.0 cm. (The path can be viewed because the gas ions in the path focus the beam by attracting electrons, and emitting light by electron capture; this method is known as the ‘fine beam tube’ method.) Determine e/m from the data.

Suppose the loop in Exercise 6.4 is stationary but the current feeding the electromagnet that produces the magnetic field is gradually reduced so that the field decreases from its initial value of 0.3T at the rate of 0.02T s^–1. If the cut is joined and the loop has a resistance of 1.6Ω, how much power is dissipated by the loop as heat? What is the source of this power?

What is the speed of a photon with respect to another photon if:

1. The two photons are going in the same direction and.
2. They are going in opposite directions?