- AMagnetic moment and magnetic field are antiparallel.
- BMagnetic moment and magnetic field are parallel.
- CThe magnetic moment is zero.
- DThe magnetic field is zero.
Explanation:
A magnetic dipole possess maximum potential energy when its magnetic moment and the magnetic field are antiparallel. When the magnetic dipole is aligned along the magnetic field, i.e. when $θ = 180^\circ,$ it is in unstable equilibrium having maximum potential energy.
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
A long straight wire carrying current of 30A is placed in an external uniform magnetic field of induction 4 × 10–4 T. The magnetic field is acting parallel to the direction of current. The magnitude of the resultant magnetic induction in tesla at a point 2.0 cm away from the wire is
|
(a) 10–4 |
(b) 3 × 10–4 |
(c) 5 × 10–4 |
(d) 6 × 10–4 |
A 36 W galvanometer is shunted by resistance of 4W. The percentage of the total current, which passes through the galvanometer is
|
(a) 8 % |
(b) 9 % |
(c) 10 % |
(d) 91 % |
Assertion : The electric bulbs glows immediately when switch is on.
Reason : The drift velocity of electrons in a metallic wire is very high.
|
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
|
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
|
(c) If assertion is true but reason is false. |
|
(d) If the assertion and reason both are false. |
A 4 mF capacitor, a resistance of 2.5 MW is in series with 12 V battery. Find the time after which the potential difference across the capacitor is 3 times the potential difference across the resistor. [Given ln(2)= 0.693]
|
(a) 13.86 s |
(b) 6.93 s |
(c) 7 s |
(d) 14 s |
A rectangular coil of 20 turns and area of cross- section 25 sq cm has a resistance of 100 ohm. If a magnetic field which is perpendicular to the plane of the coil changes at the rate of 1000 Tesla per second, the current in the coil is
|
(a) 1.0 ampere |
(b) 50 ampere |
(c) 0.5 ampere |
(d) 5.0 ampere |
Electric room radiator which operates at 225 volts has resistance of 50 ohms. Power of the radiator is approximately
|
(a) 100 W |
(b) 450 W |
(c) 750 W |
(d) 1000 W |