- ✓charging by induction
- Bto charge by physical contact
- Ccharging by friction
- Dnone of these
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A ray of light travelling in a transparent medium falls on a surface separating the medium from air at an angle of incidence of 45°. The ray undergoes total internal reflection. If n is the refractive index of the medium with respect to air, select the possible value (s) of n from the following
|
(a) 1.5 |
(b) 1.6 |
(c) 1.3 |
(d) a, b |
For driving a current of 2 A for 6 minutes in a circuit, 1000 J of work is to be done. The e.m.f. of the source in the circuit is
|
(a) 1.38 V |
(b) 1.68 V |
(c) 2.04 V |
(d) 3.10 V |
The sensitivity of a tangent galvanometer is increased if
| (a) Number of turn decreases | (b) Number of turn increases |
| (c) Field increases | (d) None of the above |
A capacitor with air as the dielectric is charged to a potential of 100 volts. If the space between the plates is now filled with a dielectric of dielectric constant 10, the potential difference between the plates will be
|
(a) 1000 volts |
(b) 100 volts |
(c) 10 volts |
(d) Zero |
de-Broglie wavelength of a body of mass m and kinetic energy E is given by
|
(a) |
(b) |
(c) |
(d) |
Dynamo core is laminated because
|
(a) Magnetic field increases |
|
(b) Magnetic saturation level in core increases |
|
(c) Residual magnetism in core decreases |
|
(d) Loss of energy in core due to eddy currents decreases |
A person using a lens as a simple microscope sees an: