Q. No.A circular coil of wire consisting of 100 turns, each of radius 8.0 cm carries a current of 0.40 A. What is the magnitude of the magnetic field B at the centre of the coil?
1.\(3.14 \times 10^{-4} \ T\)
2.\(2.12 \times 10^{-4} \ T\)
3.\(1.41 \times 10^{-4} \ T\)
4.\(2.01 \times 10^{-4} \ T\)
1.\(3.14 \times 10^{-4} \ T\)
2.\(2.12 \times 10^{-4} \ T\)
3.\(1.41 \times 10^{-4} \ T\)
4.\(2.01 \times 10^{-4} \ T\)
Two moving coil meters, M1 and M2 have the following particulars:
R1 = 10 Ω, N1 = 30, A1 = 3.6 x 10-3 m2 and B1 = 0.25 T
R2 = 14 Ω, N2 = 42, A2 = 1.8 x 10-3 m2 and B2 = 0.50 T
( The spring constants are identical for the two meters.)
The ratio of current sensitivity (M2 to M1) is:
A square coil of side \(10~\text{cm}\) consists of \(20~\text{turns}\) and carries a current of \(12~\text{A}.\) The coil is suspended vertically and the normal to the plane of the coil makes an angle of \(30^{\circ}\) with the direction of a uniform horizontal magnetic field of magnitude \(0.80~\text{T}.\) What is the magnitude of torque experienced by the coil?
1. \(0.79~\text{N-m}\)
2. \(0.88~\text{N-m}\)
3. \(0.49~\text{N-m}\)
4. \(0.96~\text{N-m}\)
Closely wound solenoid \(80~\text{cm}\) long has \(5\) layers of windings of \(400\) turns each. The diameter of the solenoid is \(1.8~\text{cm}.\) If the current carried is \(8.0~\text A,\) the magnitude of \(B\) inside the solenoid near its centre is:
1. \(3.7 \times 10^{-2}~\text T\)
2. \(3.1 \times 10^{-2}~\text T\)
3. \(2.5 \times 10^{-2}~\text T\)
4. \(1.44 \times 10^{-2}~\text T\)
Two long and parallel straight wires \(A\) and \(B\) carrying currents of \(8.0~\text{A}\) and \(5.0~\text{A}\) in the same direction are separated by a distance of \(4.0~\text{cm}.\) The force on a \(10\) cm section of wire A is:
| 1. | \(3\times10^{-5}~\text{N}\) | 2. | \(2\times10^{-5}~\text{N}\) |
| 3. | \(3\times10^{-4}~\text{N}\) | 4. | \(2\times10^{-4}~\text{N}\) |
A \(3.0 ~\text{cm}\) wire carrying a current of \(10 ~\text A\) is placed inside a solenoid perpendicular to its axis. The magnetic field inside the solenoid is given to be \(0.27 ~\text T.\) What is the magnetic force on the wire?
1. \(8.1 \times 10^{-2} ~\text N\)
2. \(9.8 \times 10^{-2}~\text N\)
3. \(7.6 \times 10^{-2}~\text N\)
4. \(6.8 \times 10^{-2}~\text N\)
What is the magnitude of magnetic force per unit length on a wire carrying a current of \(8~\text{A}\) and making an angle of \(30^{\circ}\) with the direction of a uniform magnetic field of \(0.15~\text{T}?\)
| 1. | \(0.04~\text{N/m}\) | 2. | \(0.6~\text{N/m}\) |
| 3. | \(1.5~\text{N/m}\) | 4. | \(0.33~\text{N/m}\) |
A horizontal overhead power line carries a current of \(90\) A in the east to west direction. What is the magnitude and direction of the magnetic field due to the current \(1.5~\text{m}\) below the line?
| 1. | \(1.2 \times 10^{-5}\) T, towards north |
| 2. | \(2.1 \times 10^{-5}\) T, towards south |
| 3. | \(1.2 \times 10^{-5}\) T, towards south |
| 4. | \(2.1 \times 10^{-5}\) T, towards north |
A long straight wire in the horizontal plane carries a current of 50 A in the north to south direction. The magnitude and direction of the magnetic field at a point 2.5 m east of the wire is:
1. \(4 \times 10^{-6}~ T\) vertically upward
2. \(4 \times 10^{-6} ~T\) vertically downward
3. \(3 \times 10^{-6} ~T\) vertically upward
4. \(3 \times 10^{-6} ~T\) vertically downward
A long straight wire carries a current of \(35~\text{A}.\) The magnitude of the magnetic field at a point \(20~\text{cm}\) from the wire is:
1. \(3.5 \times 10^{-6} ~\text T\)
2. \(3.5 \times 10^{-5} ~\text T\)
3. \(4.5 \times 10^{-6} ~\text T\)
4. \(4.5 \times 10^{-5} ~\text T\)
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