Explanation:
The most important features of superconductor is:
In a superconductor, the electric resistance is equal to zero. This is why an electric current can circulate forever in a superconducting ring even when the battery has been unplugged.
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A parallel plate capacitor of plate area A and plate separation d is charged to potential V and then the battery is disconnected. A slab of dielectric constant k is then inserted between the plates of the capacitors so as to fill the space between the plates. If Q, E and W denote respectively, the magnitude of charge on each plate, the electric field between the plates (after the slab is inserted) and work done on the system in question in the process of inserting the slab, then state incorrect relation from the following
|
(a) |
(b) |
(c) |
(d) |
Light coming from a star is observed to have a wavelength of 3737 Å, while its real wavelength is 3700 Å. The speed of the star relative to the earth is [Speed of light 3 
]
|
(a) 3 |
(b) 3 |
(c) 3.7 |
(d) 3.7 |
Rate of change of torque τ with deflection θ is maximum for a magnet suspended freely in a uniform magnetic field of induction B, when
| (a) θ = 0° | (b) θ = 45° | (c) θ = 60° | (d) θ = 90° |
Consider the circuits shown in the figure. Both the circuits are taking same current from battery but current through R in the second circuit is 
th of current through R in the first circuit. If R is 11 W, the value of R1
|
(a) 9.9 W |
(b) 11 W |
(c) 8.8 W |
(d) 7.7 W |
Two point charges of 20μC and 80 μC are 10 cm apart. Where will the electric field strength be zero on the line joining the charges from 20 μC charge
|
(a) 0.1 m |
(b) 0.04 m |
(c) 0.033 m |
(d) 0.33 m |
A condenser of capacity 50μF is charged to 10 volts. Its energy is equal to
|
(a) 2.5 |
(b) 2.5 |
(c) 5 |
(d) 1.2 |
