- ACharge cannot be destroyed.
- BCharge exists on particles.
- CThere is a minimum permissible charge on a particle.
- DCharge, which is a fraction of a coulomb is not possible.
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The rate of disintegration was observed to be
disintegrations per sec when its half life period is 1445 years. The original number of particles are
|
(a) 8.9 |
(b) 6.6 |
(c) 1.4 |
(d) 1.2 |
There is a uniform electric field of strength along y-axis. A body of mass 1g and charge
is projected into the field from origin along the positive x-axis with a velocity 10m/s. Its speed in m/s after 10s is (Neglect gravitation)
|
(a) 10 |
(b) 5 |
(c) 10 |
(d) 20 |
A small coil C with N = 200 turns is mounted on one end of a balance beam and introduced between the poles of an electromagnet as shown in figure. The cross sectional area of coil is A= 1.0 cm2, length of arm OA of the balance beam is l = 30 cm. When there is no current in the coil the balance is in equilibrium. On passing a current I = 22 mA through the coil the equilibrium is restored by putting the additional counter weight of mass ∆m = 60 mg on the balance pan. Find the magnetic induction at the spot where coil is located.

|
(a) 0.4 T |
(b) 0.3 T |
(c) 0.2 T |
(d) 0.1 T |
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 |
A circular loop of area
carrying a current of 10 A, is held perpendicular to a magnetic field of intensity 0.1T. The torque acting on the loop is
|
(a) Zero |
(b) 0.01 N-m |
(c) 0.001 N-m |
(d) 0.8 N-m |
One plate of parallel plate capacitor is smaller than other, then charge on smaller plate will be
|
(a) Less than other |
|
(b) More than other |
|
(c) Equal to other |
|
(d) Will depend upon the medium between them |
In a P-N junction diode if P region is heavily doped than n region then the depletion layer is
|
(a) Greater in P region |
|
(b) Greater in N region |
|
(c) Equal in both region |
|
(d) No depletion layer is formed in this case |