Electric Charges and Fields — Physics STD 12 Science — Question

Which of the following is correct when one cell is wrongly connected in series circuit?

A magnetic dipole of length 10cm has pole strength of 20Am. Find the magnetic moment of the dipole.

A nucleus  emits one α  and one β  particles. The resulting nucleus is

(a)

(b)

(c)

(d)

A galvanometer with a resistance of 12 W gives full scale deflection when a current of 3 mA is passed. It is required to convert it into a voltmeter which can read up to 18 V.  the resistance to be connected is

(a) 6000 W

(b) 5988 W

(c) 5000 W

(d) 4988 W

A capacitor is charged by using a battery which is then disconnected. A dielectric slab is introduced between the plates which results in:

Which is the best conductor of electricity?

Which among the following has a relative permeability much larger than 1?

Curies law can be written as

(a) x ∝ (T -

(b) x ∝

(c) x ∝

(d) x ∝ T

Two parallel conductors A and B of equal lengths carry currents I and 10 I, respectively, in the same direction. Then

(a) A and B will repel each other with same force

(b) A and B will attract each other with same force

(c) A will attract B, but B will repel A

(d) A and B will attract each other with different forces

A wire of diameter 0.02 metre contains 10²⁸ free electrons per cubic metre. For an electrical current of 100 A, the drift velocity of the free electrons in the wire is nearly

(a) 1 × 10–19 m/s

(b) 5 × 10–10 m/s

(c) 2 × 10–4 m/s

(d) 8 ×103 m/s