Current in a circuit falls from 5.0 A to 0.0 A in 0.1 s. If an average emf of 200 V is induced, the self-inductance of the circuit is:

A rectangular wire loop of sides 8 cm and 2 cm with a small cut is moving out of a region of the uniform magnetic field of magnitude 0.3 T directed normal to the loop. What is the emf developed across the cut if the velocity of the loop is 1 cm/s in a direction normal to the longer side?

$$\begin{gathered} \left(1\right) 2.4\times {10}^{-4} V \\ \left(2\right) 2.0\times {10}^{-3} V \\ \left(3\right) 1.3\times {10}^{-4} V \\ \left(4\right) 1.7\times {10}^{-3} V \end{gathered}$$

A jet plane is traveling towards the west at a speed of 1800 km/h. What is the voltage difference developed between the ends of the wing having a span of 25 m, if the Earth’s magnetic field at the location has a magnitude of 5 × 10^–4 T and the dip angle is 30°.

$$\begin{gathered} \left(1\right) 2.712 V \\ \left(2\right) 3.125 V \\ \left(3\right) 1.112 V \\ \left(4\right) 3.011 V \end{gathered}$$

A pair of adjacent coils has a mutual inductance of 1.5 H. If the current in one coil changes from 0 to 20 A in 0.5 s, what is the change of flux linkage with the other coil?

If a loop changes from an irregular shape to a circular shape, then magnetic flux linked with it:

A line charge λ per unit length is lodged uniformly onto the rim of a wheel of mass M and radius R. The wheel has light non-conducting spokes and is free to rotate without friction about its axis (as shown in the figure). A uniform magnetic field extends over a circular region within the rim. It is given by,

$$\begin{gathered} \overrightarrow{B}=B_0 \hat{k} \left(r\le a; a<R\right) \\ = 0 \left(otherwise\right) \end{gathered}$$

What is the angular velocity of the wheel after the field is suddenly switched off?

$$\begin{gathered} \left(1\right) -\frac{2\pi B_0{a}^2\lambda }{MR}\hat{k} \\ \left(2\right) -\frac{\pi B_0{a}^2\lambda }{MR}\hat{k} \\ \left(3\right) -\frac{2B_0{a}^2\lambda }{MR}\hat{k} \\ \left(4\right) -\frac{2B_0{a}^2\lambda }{\pi MR}\hat{k} \end{gathered}$$

A metal disc rotates freely, between the poles of a magnet in the direction indicated. Brushes P and Q makes contact with the edge of the disc and the metal axle. What current, if any, flows through R?

Two identical inductance currents  vary with time according to linear laws (as shown in figure). In which of two inductances is the self induction emf greater?

Figure shows a uniform magnetic field B confined to a cylindrical volume and is increasing at a constant rate. The instantaneous acceleration experienced by an electron placed at P is:

A straight wire carries a current of 50 A and the loop is moved to the right with a constant velocity, v= 10 m/s. the induced emf in the loop at the instant when x = 0.2 m, is:
 

$$\begin{gathered} \left(1\right) 3.4\times {10}^{-5} V \\ \left(2\right) 1.7\times {10}^{-5} V \\ \left(3\right) 1.7\times {10}^{-4} V \\ \left(4\right) 3.4\times {10}^{-4} V \end{gathered}$$

An air-cored solenoid having a length of 30 cm whose area is $25 c{m}^2,$ and the number of turns is 500 carries a current of 2.5 A. Suddenly the current is turned off and the time taken for it is ${10}^{-3} s.$ What would be the average value of the induced back-emf across the ends of the open switch in the circuit? (Neglect the variation in the magnetic field near the ends of the solenoid.)

Figure shows a metal rod PQ resting on the smooth rails AB and positioned between the poles of a permanent magnet. The rails, the rod, and the magnetic field are in three mutually perpendicular directions. A galvanometer G connects the rails through a switch K. Length of the rod = 15 cm, B = 0.50 T, resistance of the closed-loop containing the rod = 9.0 mΩ. Assume the field to be uniform.

What is the magnitude of the induced emf if we will keep the K open and the rod is moved with the speed of 12 cm/s in the direction shown in the figure?

Figure shows a metal rod PQ resting on the smooth rails AB and positioned between the poles of a permanent magnet. The rails, the rod, and the magnetic field are in three mutually perpendicular directions. A galvanometer G connects the rails through a switch K. Length of the rod = 15 cm, B = 0.50 T, resistance of the closed-loop containing the rod = 9.0 mΩ. Assume the field to be uniform.

What is the emf induced in the moving rod if the direction of the magnetic field is changed from perpendicular to parallel to the rails?

It is desired to measure the magnitude of the field between the poles of a powerful loudspeaker magnet. A small flat search coil of area $2 c{m}^2$ with 25 closely wound turns, is positioned normal to the field direction, and then quickly snatched out of the field region. Equivalently, one can give it a quick 90° turn to bring its plane parallel to the field direction). The total charge flown in the coil (measured by a ballistic galvanometer connected to the coil) is 7.5 mC. The combined resistance of the coil and the galvanometer is 0.50 $\Omega$. The field strength of the magnet is:

Dimensional formula of magnetic flux is:

A cylindrical magnet is kept along the axis of a circular coil. On rotating the magnet about its axis, the coil will have induced in it:

A bar magnet is made to fall through a long surface copper tube. The speed (v) of the magnet as a function of time (t) is best represented by

A long solenoid has self inductance L. If its length is doubled keeping total number of turns constant then its new self inductance will be:

A solenoid has 2000 turns wound over a length of 0.3 m. The area of its cross section is $1.2\times {10}^{-3} {\mathrm{m}}^2$. Around its central section of a coil of 300 turns is wound. If an initial current of 2A is reversed in 0.25 s, the e.m.f. induced in the coil is equal to

With the decrease of current in the primary coil from 2 A to zero in 0.01s, the e.m.f. generated in the secondary coil is 1000 V. The mutual inductance of the two coil is?

The coefficient of self induction of two inductor coils are 20 mH and 40 mH respectively. If the coils are connected in series so as to support each other and the resultant inductance is 80 mH then the value of mutual inductance between the coils will be:

A coil and a bulb are connected in series with a 12 volt direct current source. A soft iron core is now inserted in the coil. Then

A uniform magnetic field B is directed out of the page. A metallic wire has the shape of a square frame and is placed in the field as shown. While the shape of the wire is steadily transformed into a circle in the same plane, the current in the frame:

The dimension of the ratio of magnetic flux and the resistance is equal to that of:

Three identical coils A, B and C carrying currents are placed coaxially with their planes parallel to one another. A and C carry currents as shown. B is kept fixed, while A and C both are moved towards B with the same speed. Initially, B is equally seperated from A and C. The direction of the induced current in the coil B is :

In the arrangement shown in given figure, current from A to B is increasing in magnitude. Induced current in the loop will:

Two identical coaxial circular loops carry a current 'i' each circulating in the same direction. If the loops approach each other:

A conducting wire frame is placed in a magnetic field which is directed into the plane of the paper (see figure). The magnetic field is increasing at a constant rate. The directions of induced currents in wires AB and CD are

Two identical conductors P and Q are placed on two frictionless(conducting) rails R and S in a uniform magnetic field directed into the plane. If P is moved in the direction shown in the figure with a constant speed, then rod Q:

Two circular coils A and B are facing each other as shown in figure. The current i through A can be altered. Then-