Semiconductor Electronics: Materials, Devices and Simple Circuits — Physics STD 12 Science — Question

Digital signals are :

Magnitude of produced magnetic field at any point inside a solenoid depends on:

Assertion   :   A metallic shield in form of a hollow shell may be built to block an electric field.

Reason       : In a hollow spherical shield, the electric field inside it is zero at every point.

(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.

(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.

(c) If assertion is true but reason is false.

(d) If the assertion and reason both are false.

Two negative charges are kept at a certain distance in the air medium. What will happen if a dielectric slab is inserted between them?

Consider the following statements A and B and identify the correct choice of the given answers

A : The width of the depletion layer in a P-N junction diode increases in forwards bias

B : In an intrinsic semiconductor the fermi energy level is exactly in the middle of the forbidden gap

(a) A is true and B is false	(b) Both A and B are false
(c) A is false and B is true	(d) Both A and B are true

The battery connections required to forward bias a pn junction are ____________:

The rate of disintegration at a given instant, is directly proportional to the number of atoms present at that instant. This is the statement of:

When cathode rays (tube voltage ~ 10 kV) collide with the anode of high atomic weight then we get

(a) Positive rays

(b) X-rays

(c) Gamma rays

(d) Canal rays

An electric heater is heated by de and ac respec- tively. The potential difference applied across the ends of heater for both ac and de is same. Heat gener- ated per second will be more:

The focal length of a normal eye-lens is about:

1. 1mm.
2. 2cm.
3. 25cm.
4. 1m.