A bar magnet of length ‘l’ and magnetic dipole moment ‘M’ is bent in the form of an arc as shown in the figure. The new magnetic dipole moment will be:
1. 3M/
2. 2M/l
3. M/2
4. M
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NEET MCQ Books for XIth & XIIth Physics, Chemistry & BiologyA vibration magnetometer placed in a magnetic meridian has a small bar magnet. The magnet executes oscillations with a time period of 2 s in the earth's horizontal magnetic field of 24 T. When a horizontal field of 18 T is produced opposite to the earth's field by placing a current-carrying wire, the new time period of the magnet will be:
1. 1 s
2. 2 s
3. 3 s
4. 4 s
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NEET MCQ Books for XIth & XIIth Physics, Chemistry & BiologyPrefer Books for Question Practice? Get NEETprep's Unique MCQ Books with Online Audio/Video/Text Solutions via Telegram Bot
NEET MCQ Books for XIth & XIIth Physics, Chemistry & BiologyA magnet is parallel to a uniform magnetic field. If it is rotated by 60°, the work done is 0.8 J. How much work is done in moving it 30° further?
1.
2. 0.4 J
3. 8 J
4. 0.8 ergs
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NEET MCQ Books for XIth & XIIth Physics, Chemistry & BiologyThe current of 30 A is flowing in a vertical straight wire. If the horizontal component of the earth's magnetic field is 2 x 10-5 Tesla, then the position of the null point will be:
1. 0.9 m
2. 0.3 mm
3. 0.3 cm
4. 0.3 m
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NEET MCQ Books for XIth & XIIth Physics, Chemistry & BiologyA closely wound solenoid of 2000 turns and area of cross-section 1.5 × 10–4 m2 carries a current of 2.0 A. It is suspended through its centre and perpendicular to its length, allowing it to turn in a horizontal plane in a uniform magnetic field 5 × 10–2 tesla making an angle of 30° with the axis of the solenoid. The torque on the the solenoid will be:
1. 3 × 10–3 Nm
2. 1.5 × 10–3 Nm
3. 1.5 × 10–2 Nm
4. 3 × 10–2 Nm
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NEET MCQ Books for XIth & XIIth Physics, Chemistry & BiologyA thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field. Hence the rod gains gravitational potential energy. The work required to do this comes from:
1. | the current source |
2. | the magnetic field |
3. | the lattice structure of the material of the rod |
4. | the induced electric field due to the changing magnetic field. |
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NEET MCQ Books for XIth & XIIth Physics, Chemistry & BiologyA frog can be levitated in a magnetic field produced by a current in a vertical solenoid placed below the frog. This is possible because the body of the frog behaves as:
1. paramagnetic
2. diamagnetic
3. ferromagnetic
4. none of these
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NEET MCQ Books for XIth & XIIth Physics, Chemistry & BiologyI: | Magnetic flux linked with a closed surface is always zero. |
II: | Magnetic monopole does not exist. |
1. | Both I and II are true and II is the correct explanation for I. |
2. | Both I and II are true and II is not the correct explanation for I. |
3. | I is true but II is false. |
4. | I is false but II is true. |
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NEET MCQ Books for XIth & XIIth Physics, Chemistry & BiologyA current carrying coil is placed with its axis perpendicular to N-S direction. Let horizontal component of earth's magnetic field be and magnetic field inside the loop be H. If a magnet is suspended inside the loop, it makes angle with H. Then
1.
2.
3.
4.
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NEET MCQ Books for XIth & XIIth Physics, Chemistry & Biology