Magnetic Field Due to Solenoid & Toroid

Q. The energy stored in the magnetic field of solenoid 30 cm long and 3 cm diameter wound with 1000 turns of wire carrying a current of 10 A is

1. 0.015 J
2. 0.15 J
3. 0.5 J
4. 1.15 J

Q. The inductance of a long solenoid of length 1000 mm wound uniformly with 3000 turns on a cylindrical paper tube of 60 mm diameter is

1. 3.2 $\mu$H
2. 3.2 mH
3. 32.0 mH
4. 3.2 H

Q. A solenoid of 2500 turns wound uniformly over a length of 0.5 m on a cylindrical paper tube, 4cm in diameter. The inductance of the solenoid is ________mH (Assume air medium )

1. 19.7

Q. Two identical copper wires $W_{1}and{W}_2$ placed in parallel as shown in the figure, carry currents I and 2I, respectively. In opposite directions. If the two wires are separated by a distance of 4r, then the magnitude of the magnetic field $\overrightarrow{B}$ between the wires at a distance r from $W_1$ is

1. $\frac{{\mu }_0^2{I}^2}{2\pi r^2}$

2. $\frac{6{\mu }_{0}I}{5\pi r}$

3. $\frac{{\mu }_{0}I}{6\pi r}$

4. $\frac{5{\mu }_{0}I}{6\pi r}$

Q. An ideal solenoid with 300 turns, length 0.50 m and a circular cross-section of radius 0.02 m is considered. The inductance L of the solenoid is_____ $\mu H$.

1. 284.24
2. 28.42
3. 2.842
4. none of the above