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 wire has a resistance of 12 ohm. It is bent in the form of equilateral triangle. The effective resistance between any two corners of the triangle is
|
(a) 9 ohms |
(b) 12 ohms |
(c) 6 ohms |
(d) 8/3 ohms |
Earth's magnetic field always has a horizontal component except at or Horizontal component of earth's magnetic field remains zero at
| (a) Equator | (b) Magnetic poles | (c) A latitude of 60o | (d) An altitude of 60o |
The core of a transformer is laminated to reduce energy losses due to
|
(a) Eddy currents |
(b) Hysteresis |
|
(c) Resistance in winding |
(d) None of these |
Which of the following cannot cause fission in a heavy nucleus
| (a) a-particle | (b) Proton | (c) Deutron | (d) Laser rays |
As shown in the figure, a magnet is moved with a fast speed towards a coil at rest. Due to this induced electromotive force, induced current and induced charge in the coil is E, I and Q respectively. If the speed of the magnet is doubled, the incorrect statement is
|
(a) E increases |
(b) I increases |
(c) Q remains same |
(d) Q increases |
The charge on electron was discovered by
|
(a) J.J. Thomson |
(b) Neil Bohr |
(c) Millikan |
(d) Chadwick |
An atomic nucleus 
emits several a and b radiations and finally reduces to 
. It must have emitted
|
(a) 4a and 2b |
(b) 6a and 4b |
(c) 8a and 24b |
(d) 4a and 16b |