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 cm long has 5 layers of windings of 400 turns each. The diameter of the solenoid is 1.8 cm. If the current carried is 8.0 A, the magnitude of B inside the solenoid near its centre is:

1.\(3.7 \times 10^{-2} \ T\)
2.\(3.1 \times 10^{-2} \ T\)
3.\(2.5 \times 10^{-2} \ T\)
4.\(1.44 \times 10^{-2} \ T\)

Two long and parallel straight wires A and B carrying currents of \(8.0\) A and \(5.0\) A in the same direction are separated by a distance of \(4.0\) cm. The force on a \(10\) cm section of wire A is:
1. \(3\times10^{-5}\) N
2. \(2\times10^{-5}\) N
3. \(3\times10^{-4}\) N
4. \(2\times10^{-4}\) N

A 3.0 cm wire carrying a current of 10 A is placed inside a solenoid perpendicular to its axis. The magnetic field inside the solenoid is given to be 0.27 T. What is the magnetic force on the wire?

1.\(8.1 \times 10^{-2} \ N\)
2.\(9.8 \times 10^{-2} \ N\)
3. \(7.6 \times 10^{-2} \ N\)
4.\(6.8 \times 10^{-2} \ N\)

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 \(0.15~\text{T}\)?

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 \(1.5\) 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 \(35\) A. The magnitude of the magnetic field at a point \(20\) cm from the wire is:
1. \(3.5 \times 10^{-6} \) T
2. \(3.5 \times 10^{-5} \) T
3. \(4.5 \times 10^{-6} \) T
4.\(4.5 \times 10^{-5} \) T

A straight horizontal conducting rod of length 0.45 m and mass 60 g is suspended by two vertical wires at its ends. A current of 5.0 A is set up in the rod through the wires. (a) What magnetic field should be set up normally to the conductor in order that the tension in the wires is zero?

1. 0.13 T
2. 0.06 T
3. 0.26 T
4. 0.18 T

The wires which connect the battery of an automobile to its starting motor carry a current of \(300~\text{A}\) (for a short time). What is the force per unit length between the wires if they are \(70~\text{cm}\) long and \(1.5~\text{cm}\) apart?
1. \(2.2~\text{N/m}\)
2. \(4.7~\text{N/m}\)
3. \(3.2~\text{N/m}\)
4. \(1.2~\text{N/m}\)