An electron moves on a straight-line path XY as shown. The abcd is a coil adjacent to the path of electrons. What will be the direction of current if any, induced in the coil?
1. | abcd |
2. | adcb |
3. | The current will reverse its direction as the electron goes past coil |
4. | No current included |
A conducting square frame of side \(a\) and a long straight wire carrying current \(I\) are located in the same plane as shown in the figure. The frame moves to the right with a constant velocity \(v.\) The emf induced in the frame will be proportional to:
A thin semicircular conducting the ring \((PQR)\) of radius \(r\) is falling with its plane vertical in a horizontal magnetic field \(B,\) as shown in the figure. The potential difference developed across the ring when it moves with speed \(v\) is:
1. | zero |
2. | \(Bv\pi r^{2}/2\) and \(P\) is at a higher potential. |
3. | \(\pi rvB\) and \(R\) is at a higher potential. |
4. | \(2BvR\) and \(R\) is at higher potential. |
A coil of self-inductance L is connected in series with a bulb B and an AC source. The brightness of the bulb decreases when:
1. | number of turns in the coil is reduced. |
2. | a capacitance of reactance XC = XL is included in the same circuit. |
3. | an iron rod is inserted in the coil. |
4. | frequency of the AC source is decreased. |
1. | twice per revolution. |
2. | four times per revolution. |
3. | six times per revolution. |
4. | once per revolution. |
A coil of resistance \(400~\Omega\) is placed in a magnetic field. The magnetic flux \(\phi~\text{(Wb)}\) linked with the coil varies with time \(t~\text{(s)}\) as \(\phi=50t^{2}+4.\) The current in the coil at \(t=2~\text{s}\) is:
1. \(0.5~\text{A}\)
2. \(0.1~\text{A}\)
3. \(2~\text{A}\)
4. \(1~\text{A}\)
The current (I) in the inductance is varying with time according to the plot shown in the figure.
1. | 2. | ||
3. | 4. |
In a coil of resistance \(10\) \(\Omega\), the induced current developed by changing magnetic flux through it is shown in the figure as a function of time. The magnitude of change in flux through the coil in Weber is:
1. \(2\)
2. \(6\)
3. \(4\)
4. \(8\)
The current \(i\) in a coil varies with time as shown in the figure. The variation of induced emf with time would be:
1. | 2. | ||
3. | 4. |