Current Electricity — Physics STD 12 Science — Question

6 A particle of charge q and mass m moves rectilinearly under the action of electric field E = A – Bx, where A and B are positive constants and x is distance from the point where particle was initially at rest then the distance travelled by the particle before coming to rest and acceleration of particle at that moment are respectively:

The radius of circular path of an electron when subjected to a perpendicular magnetic field is

(a)

(b)

(c)

(d)

The capacitance of a parallel plate capacitor is 12μF. If the distance between the plates is doubled and area is halved, then new capacitance will be

(a) 8μF

(b) 6μF

(c) 4μF

(d) 3μF

Identify the factor on which the capacitance of a parallel plate capacitor does not depend.

To form a composite 16Μf, 1000 V  capacitor from a supply of identical capacitors marked 8 μF, 250 V we require a minimum number of capacitors

(a) 40

(b) 32

(c) 8

(d) 2

In given figure, the potentiometer wire AB has a resistance of 5 W and length 10 m. The balancing length AM for the emf of 0.4 V is

(a) 0.4 m

(b) 4 m

(c) 0.8 m

(d) 8 m

When the frequency of AC is doubled, the impedance of an LCR series circuit:

Every atom makes one free electron in copper. If 1.1 ampere current is flowing in the wire of copper having 1 mm diameter, then the drift velocity (approx.) will be (Density of copper  = 9   and atomic weight = 63)

(a) 0.3 mm/sec

(b) 0.1 mm/sec

(c) 0.2 mm/sec

(d) 0.2 mm/sec