- 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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A highly conducting ring of radius R is perpendicular to and concentric with the axis of a long solenoid as shown in fig. The ring has a narrow gap of width d in its circumference. The solenoid has cross sectional area A and a uniform internal field of magnitude B0. Now beginning at t = 0, the solenoid current is steadily increased to so that the field magnitude at any time t is given by B(t) = B0 + at where α > 0. Assuming that no charge can flow across the gap, the end of ring which has excess of positive charge and the magnitude of induced e.m.f. in the ring are respectively

|
(a) X, A𝛼 |
(b) X, pR2𝛼 |
(c) Y, 𝜋A2𝛼 |
(d) Y, pR2𝛼 |
Given below are symbols for some logic gates

The XOR gate and NOR gate respectively are
|
(a) 1 and 2 |
(b) 2 and 3 |
(c) 3 and 4 |
(d) 1 and 4 |
A vertical straight conductor carries a current vertically upwards. A point P lies to the east of it at a small distance and another point Q lies to the west at the same distance. The magnetic field at P is
| (a) Greater than at Q |
| (b) Same as at Q |
| (c) Less than at Q |
| (d) Greater or less than at Q depending upon the strength of the current |
The temperature coefficient of resistance for a wire is 0.00125/℃. At 300K its resistance is 1 ohm. The temperature at which the resistance becomes 2 ohm is
|
(a) 1154 K |
(b) 1100 K |
(c) 1400 K |
(d) 1127 K |
The largest distance between the interatomic planes of a crystal is 10-7cm. The upper limit for the wavelength of X-rays which can be usefully studied with this crystal is
| (a) 1 Å | (b) 2 Å | (c) 10 Å | (d) 20 Å |