Electric Charges and Fields — Physics STD 12 Science — Question

The magnetic susceptibility is negative for

(a) Paramagnetic materials

(b) Diamagnetic materials

(c) Ferromagnetic materials

(d) Paramagnetic and ferromagnetic materials

If the dielectric constant and dielectric strength be denoted by k and x respectively, then a material suitable for use as a dielectric in a capacitor must have

(a) High k and high x

(b) High  k and low x

(c) Low k and low x

(d) Low k  and high  x

The thermal radiation emitted by a body is proportional to Tⁿ where Tis its absolute temperature. The value of n is exactly 4 for:

1. A blackbody.
2. All bodies.
3. Bodies painted black only.
4. Polished bodies only.

The reactance of a circuit is zero. It is possible that the circuit contains:

What should be the current in a circular coil of radius 5cm to annul  

(a) 0.4 A

(b) 4 A

(c) 40 A

(d) 1 A

A. Current flow inside the capacitor due to accumulation of charges on the capacitor walls is called displacement current.
B. Current due to the flow of electrons due to some potential difference is called as conduction current. 
C. Displacement current came into existence when Maxwell observed that if a magnetic compass is placed between the capacitors the needle gets deflected which signifies presence of magnetic fields which would possibly caused due to some changing current.
D. Displacement current change the actual motion of electric charges.
Which of the above statement(s) is/ are correct?

The wavelength of the first line of Balmer series is 6563 . The Rydberg constant for hydrogen is about

(a) 1.09

(b) 1.09

(c) 1.09

(d) 1.09

Which of the following is an example of a direct band gap intrinsic semiconductor?

Two particles A and B of masses   and  respectively and having the same charge are moving in a plane. A uniform magnetic field exists perpendicular to this plane. The speeds of the particles are   and   respectively, and the trajectories are as shown in the figure. Then

(a)	(b)
(c)  and	(d)  and

A hydrogen atom in its ground state absorbs 10.2 eV of energy. The orbital angular momentum is increased by (Given Planck constant h = 6.6 J - sec)

(a) 1.05   J-sec

(b) 3.16   J-sec

(c) 2.11   J-sec

(d) 4.22   J-sec