Explanation:
The concept of holes was introduced so as to occupy the empty spaces left by the missing electron. For example, in a valence band, when an electron jumps from valence to conduction band, an empty space is created in valence band which is occupied by a hole.
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
The ratio of de-Broglie wavelength of a a-particle to that of a proton being subjected to the same magnetic field so that the radii of their path are equal to each other assuming the field induction vector 
is perpendicular to the velocity vectors of the a-particle and the proton is
|
(a) 1 |
(b) |
(c) |
(d) 2 |
Light of different colours propagates through air
|
(a) With the velocity of air |
|
(b) With different velocities |
|
(c) With the velocity of sound |
|
(d) Having the equal velocities |
A plane mirror reflecting a ray of incident light is rotated through an angle θ about an axis through the point of incidence in the plane of the mirror perpendicular to the plane of incidence, then
|
(a) The reflected ray rotates through an angle 2θ |
| (b) The incident ray is fixed |
| (c) The reflected ray does not rotate |
| (d) a, b |
Assertion : Self-inductance is called the inertia of electricity.
Reason : Self-inductance is the phenomenon, according to which an opposing induced e.m.f. is produced in a coil as a result of change in current or magnetic flux linked in the coil.
|
(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 wave of hydrogen atom comes from infinity into the first orbit then the value of wave number is
|
(a) 109700 cm–1 |
(b) 1097cm–1 |
(c) 109 cm–1 |
(d) None of these |
