Semiconductor Electronic: Material, Devices And Simple Circuits — Physics STD 12 Science — Question

Assertion :   Electric conduction in gases is possible at normal pressure.

Reason     : The electric conduction in gases depends only upon the potential difference between the electrodes.

(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.

When the length and area of cross-section both are doubled, then its resistance

(a) Will become half	(b) Will be doubled
(c) Will remain the same	(d) Will become four times

A triode is operated in the linear region of its characteristics. If the plate voltage is slightly increased, the dynamic plate resistance will:

A diverging beam of light from a point source S having divergence angle a, falls symmetrically on a glass slab as shown.  The angles of incidence of the two extreme rays are equal.  If the thickness of the glass slab is t and the refractive index n, then the divergence angle of the emergent beam is

(a) Zero

(b) α

(c)

(d) 2

The voltage gain of the following amplifier is

(a) 10

(b) 100

(c) 1000

(d) 9.9

 Pick out the correct increasing order of energy of electromagnetic waves from the following:

For a given material, the energy and wavelength of characteristic X-rays satisfy:

A solenoid of length l metre has self-inductance L henry. If number of turns are doubled, its self inductance

(a) Remains same	(b) Becomes 2L henry
(c) Becomes 4L henry	(d) Becomes   henry

Given below are the symbols of a few electronic components. Which of these components denote a variable inductor?

A hollow sphere of charge does not produce an electric field at any

(a) Point beyond 2 metres	(b) Point beyond 10 metres
(c) Interior point	(d) Outer point