Atoms — Physics STD 12 Science — Question

For the production of characteristic   X-ray, the electron transition is

(a) n = 2 to n = 1

(b) n = 3 to  n = 2

(c) n = 3 to n = 1

(d) n = 4 to n = 1

A 10 metre wire kept in east-west falling with velocity 5 m/sec perpendicular to the field 0.3 .  The induced e.m.f. across the terminal will be

(a)  0.15 V

(b) 1.5 mV

(c)  1.5 V

(d) 15.0 V

The current inside a copper voltameter

(a) Is half the outside value	(b) Is the same as the outside value
(c) Is twice the outside value	(d) Depends on the concentration of

The figures represent three cases of a ray passing through a prism of angle A. The case corresponding to minimum deviation is

(a) 1

(b) 2

(c) 3

(d) None of these

If a 2 kW boiler is used everyday for 1 hour, then electrical energy consumed by boiler in thirty days is

(a) 15 unit

(b) 60 unit

(c) 120 unit

(d) 240 unit

The work function for tungsten and sodium are 4.5 eV and 2.3 eV respectively. If the threshold wavelength λ  for sodium is , the value of  λ for tungsten is

(a) 5893 Å

(b) 10683 Å

(c) 2791 Å

(d) 528 Å

The current sensitibility of a moving coil galanometer increases with decrease in:

In a projectile motion the velocity:

1. Is always perpendicular to the acceleration.
2. Is never perpendicular to the acceleration.
3. Is perpendicular to the acceleration for one instant only.
4. Is perpendicular to the acceleration for two instants.

The net charge on a condenser is:

Which one of the following nuclear reactions is a source of energy in the sun

(a)

(b)

(c)

(d)