Potential gradient is defined as
|
(a) Fall of potential per unit length of the wire |
|
(b) Fall of potential per unit area of the wire |
|
(b) Fall of potential per unit area of the wire |
|
(d) Potential at any one end of the wire |
(a) Fall of potential per unit length of the wire
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A current of 5 ampere is flowing in a wire of length 1.5 metres. A force of 7.5 N acts on it when it is placed in a uniform magnetic field of 2 Tesla. The angle between the magnetic field and the direction of the current is
|
(a) 30° |
(b) 45° |
(c) 60° |
(d) 90° |
Two opposite and equal charges 4 × 
when placed 2 
cm away, form a dipole. If this dipole is placed in an external electric field 4 
, the value of maximum torque and the work done in rotating it through 180° will be
|
(a) 64 |
(b) 32 |
|
(c) 64 |
(d) 32 |
A capacitor of capacitance C1 = 1mF can with stand maximum voltage V1 = 6kV (kilo-volt) and another capacitor of capacitance C2 = 3mF can withstand maximum voltage V2 = 4 kV. When the two capacitors are connected in series, the combined system can withstand a maximum voltage of
|
(a) 4kV |
(b) 6kV |
(c) 8kV |
(d) 10kV |
Carbon -14 decays with half-life of about 5,800 years. In a sample of bone, the ratio of carbon -14 to carbon -12 is found to be 
of what it is in free air. This bone may belong to a period about x centuries ago, where x is nearest to
|
(a) 2 × 58 |
(b) 58 |
(c) 58/2 |
(d) 3 × 58 |
Holes are charge carriers in
|
(a) Intrinsic semiconductors |
(b) P-type semiconductors |
|
(c) Metals |
(d) a, b |
The mutual inductance of an induction coil is 5H. In the primary coil, the current reduces from 5A to zero in 
. What is the induced emf in the secondary coil
|
(a) 2500 V |
(b) 25000V |
(c) 2510V |
(d) Zero |
An electron having charge ‘e’ and mass ‘m’ is moving in a uniform electric field E. Its acceleration will be
|
(a) |
(b) |
(c) |
(d) |
