Atoms — Physics STD 12 Science — Question

As the mass number A increases, which of the following quantities related to a nucleus do not change?

1. Mass.
2. Volume.
3. Density.
4. Binding energy.

The magnetic moment of atomic neon is

(a) Zero

(b) μB/2

(c) μB

(d) 3μB/2

The radii of curvature of a convex lens are 15 cm and 30 cm respectively. Its refractive index is 1.5 . The focal length of the lens will be :

The work done by all the forces (external and internal) on a system equals the change in:

1. Total energy.
2. Kinetic energy.
3. Potential energy.
4. None of these.

Two wires of same substance are given. Length and diameter of first wire are double that of the other. The resistance of first is __________ of other.

Which of the following is true for number of spectral lines in going form Layman series to Pfund series

(a) Increases	(b) Decreases
(c) Unchanged	(d) May decreases or increases

Which one is in forward bias

(a)

(b)

(c)

(d) None of these

A conductor ABOCD moves along its bisector with a velocity of 1 m/s through a perpendicular magnetic field of 1 wb/m², as shown in fig. If all the four sides are of 1m length each, then the induced emf between points A and D is

(a) 0

(b) 1.41 volt

(c) 0.71 volt

(d) None of the above

Impedance of L-R circuit is :

To increase both the resolving power and magnifying power of a telescope: