Explanation:
Justification of (a) and (b):
Investigators and experimenters have failed to find any sign of magnetic monopoles. So, we can assume that magnetic monopoles are only a mathematical assumption.
A magnetic field is produced by the motion of an electric charge only. In paramagnets or ferromagnets, the motion of an electron (charge) and the alignment of domains (bunch of charges with particular alignment) create paramagnetism and ferromagnetism, respectively.
Therefore, the only cause behind the magnetic field is the motion of an electric charge.
Denial of (c):
The north pole is equivalent to an anticlockwise current and the south pole is equivalent to a clockwise current.
Denial of (d):
A bar magnet is not equivalent to a long, straight current because the distribution and orientation of magnetic field lines do not resemble each other.
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
A group of N cells whose emf varies directly with the internal resistance as per the equation EN = 1.5 rN are connected as shown in the figure below. The current I in the circuit is
|
(a) 0.51 amp |
(b) 5.1 amp |
(c) 0.15 amp |
(d) 1.5 amp |
To draw maximum current from a combination of cells, how should the cells be grouped
|
(a) Series |
|
(b)Parallel |
|
(c) Mixed |
|
(d) Depends upon the relative values of external and internal resistance |
The following configuration of gate is equivalent to
|
(a) NAND |
(b) XOR |
(c) OR |
(d) None of these |
50 Ω and 100 Ω resistors are connected in series. This connection is connected with a battery of 2.4 volts. When a voltmeter of 100 Ω resistance is connected across 100 Ω resistor, then the reading of the voltmeter will be
|
(a) 1.6 V |
(b) 1.0 V |
(c) 1.2 V |
(d) 2.0 V |
A circular loop has a radius of 5 cm and it is carrying a current of 0.1 amp. Its magnetic moment is
|
(a) 1.32 |
(b) 2.62 |
|
(c) 5.25 |
(d) 7.85 |
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 |
