Magnetic Effects of Current - NEET Physics Questions
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Magnetic Effects of Current

Practice Questions:
Question 21: moderate

As shown in the figure, the radius of each of quarter circular arc is 2m. Find the magnetic moment of the given loop for the current in the loop :

1. 5Ο€i
2. 4Ο€i
3. 2Ο€i
4. 3Ο€i
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Question 22: moderate

A charge q coulomb moves in a circle with n revolutions per second and the radius of the circle is r metre. The magnetic field at the centre of the circle is :

1. \[\frac{2\pi q}{nr}\times10^{-7}NA^{-1}m^{-1}\]
2. \[\frac{2\pi q}{r}\times10^{-7}NA^{-1}m^{-1}\]
3. \[\frac{2\pi nq}{r}\times10^{-7}NA^{-1}m^{-1}\]
4. \[\frac{2\pi q}{r}\times NA^{-1}m^{-1}\]
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Question 23: moderate

A charged particle moves along a circle under the action of possible constant electric and magnetic fields. Which of the following are possible ?

1. E = 0, B = 0
2. E = 0, B β‰  0
3. E β‰  0, B = 0
4. E β‰  0, B β‰  0
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Question 24: moderate

Two particles Y and Z emitted by a radioactive source at P made tracks in a chamber as illustrated in the figure. A magnetic field acts downward into the paper. Careful measurements showed that both tracks were circular, the radius of Y track being half that of the Z track. Which one of the following statements is certainly true ?

1. Both particles Y and Z carried a positive charge
2. The mass of particle Z was one half that of particle Y
3. The mass of particle Z was twice that of particle Y
4. The charge of particle Z was twice that of particle Y
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Question 25: moderate

A charged particle enters a uniform magnetic field with velocity vector at an angle of 45Β° with the magnetic field. The pitch of the helical path followed by the particle is p. The radius of circle of the helix will be :

1. p/√2Ο€
2. √2p
3. p/2Ο€
4. √2p/Ο€
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Question 26: moderate

A long straight, hollow, conductor (tube) carrying a current has two sections A and C of unequal cross sections joined by a conical section B. 1, 2 and 3 are points on a line parallel to the axis of the conductor. The magnetic fields at 1, 2 and 3 have magnitudes B1, B2 and B3. Then :

1. B1 = B2 = B3
2. B1 = B2 β‰  B3
3. B1 < B2 < B3
4. B2 cannot be found unless the dimensions of the section B are known
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Question 27: moderate

Figure shows three cases, in all cases the circular part has radius r and stragiht ones are infinitely long. For the same current the ratio of field B at center P in the three cases B1 : B2 : B3 is :

1. \[\left(- \frac{\pi}{2} \right):\left( \frac{\pi}{2} \right):\left( \frac{3\pi}{4}-\frac{1}{2} \right)\]
2. \[\left(- \frac{\pi}{2}+1 \right):\left( \frac{\pi}{2}+1 \right):\left( \frac{3\pi}{4}+\frac{1}{2} \right)\]
3. \[\left(- \frac{\pi}{2} \right):\left( \frac{\pi}{2} \right):\left( \frac{3\pi}{4} \right)\]
4. \[\left(- \frac{\pi}{2}-1 \right):\left( \frac{\pi}{2}-\frac{1}{4} \right):\left( \frac{3\pi}{4}+\frac{1}{2} \right)\]
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Question 28: moderate

Find out magnetic dipole moment of given current loop.

1. \[\frac{\pi Ia^{2}}{2}\]
2. \[\frac{\pi Ia^{2}}{4}\]
3. Ο€IaΒ²
4. Zero
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Question 29: moderate

Two parallel long wires carry currents i1 and i2 with i1 > i2. When the currents are in the same
direction, the magnetic field midway between the wires is 10ΞΌT. When the direction of i2 is reversed, it becomes 40ΞΌT. the ratio i1/i2 is :

1. 3 : 4
2. 11 : 7
3. 7 : 11
4. 5 : 3
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Question 30: moderate

The magnetic field at the centre of an equilateral triangular loop of side 2L and carrying a current i is :

1. \[\frac{9\mu_{0}i}{4\pi L}\]
2. \[\frac{3\sqrt{3}\mu_{0}i}{4\pi L}\]
3. \[\frac{2\sqrt{3}\mu_{0}i}{\pi L}\]
4. \[\frac{3\mu_{0}i}{4\pi L}\]
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