A rod of length \(l\) rotates with a small but uniform angular velocity \(\omega\) about its perpendicular bisector. A uniform magnetic field \(B\) exists parallel to the axis of rotation. The potential difference between the centre of the rod and an end is:
1. zero
2. \(\frac{1}{8} \omega {B} l^{2}\)
3. \(\frac{1}{2} \omega {B} l^{2}\)
4. \(B\omega l^2\)

A rod of length \(l\) rotates with a uniform angular velocity \(\omega\) about its perpendicular bisector. A uniform magnetic field \(B\) exists parallel to the axis of rotation. The potential difference between the two ends of the rod is:
1. zero
2. \(\frac{1}{2}Bl\omega ^{2}\)
3. \(Bl\omega ^{2}\)
4. \(2Bl\omega ^{2}\)

Consider the following statements: 

Consider the situation shown in the figure. The wire \(AB\) is slid on the fixed rails with a constant velocity. If the wire \(AB\) is replaced by a semi-circular wire, the magnitude of the induced current will:

1.  increase

2.  remain the same

3.  decrease 

4.  increase or decrease depending on whether the-semicircle bulges towards the resistance or away from it 

A conducting rod is moved with a constant velocity \(v\) in a magnetic field. A potential difference appears across the two ends:

Choose the correct option from the given ones:

A metal sheet is placed in front of a strong magnetic pole. A force is needed to: 

Neglect any effect of paramagnetism, diamagnetism and gravity.
Choose the correct option. 

A rod AB moves with a uniform velocity v in a uniform magnetic field as shown in the figure.

(a)  The rod becomes electrically charged.
(b) The end A becomes positively charged.
(c) The end B becomes positively charged.
(d) The rod becomes hot because of Joule heating. 

Choose the correct option 

1. (a), (b)

2. (b) only

3. (c), (d)

4. (a), (d)