Electrostatics — Physics STD 12 Science — Question

The variation of magnetic susceptibility (x) with magnetising field for a paramagnetic substance is

(a)

(b)

(c)

(d)

The energy of an X- ray photon of wavelength 1.65 Å is (h = 6.6 , 1eV = 1.6

(a)  3.5 keV

(b) 5.5 keV

(c) 7.5 keV

(d) 9.5 keV

Complete the following sentence:

Select the correct statements. Coulomb’s law correctly describes the electric force that:
i. binds the electrons of an atom to its nucleus.
ii. binds the protons and neutrons in the nucleus of an atom.
iii. binds atoms together to form molecules.

Two PN-junctions can be connected in series by three different methods as shown in the figure. If the potential difference in the junctions is the same, then the correct connections will be

(a) In the circuit (1) and (2)	(b) In the circuit (2) and (3)
(c) In the circuit (1) and (3)	(d) Only in the circuit (1)

A horizontal rod of mass 10 gm and length 10 cm is placed on a smooth plane inclined at an angle of 60° with the horizontal, with the length of the rod parallel to the edge of the inclined plane. A uniform magnetic field of induction B is applied vertically downwards. If the current through the rod is 1.73 ampere, then the value of B for which the rod remains stationary on the inclined plane is

(a) 1.73 Tesla

(b)  Tesla

(c) 1 Tesla

(d) None of the above

The self-inductance of a coil will be less when:

If a 0.1 % increase in length due to stretching, the percentage increase in its resistance will be

(a) 0.2 %

(b) 2 %

(c) 1 %

(d) 0.1 %

With the increase in principle quantum number, the energy difference between the two successive energy levels

(a) Increases

(b) Decreases

(c) Remains constant

(d) Sometimes increases and sometimes decreases

In the case of forward biasing of PN-junction, which one of the following figures correctly depicts the direction of flow of carriers

(a)

(b)

(c)

(d)