The EMF generated in a moving rod within a uniform magnetic field \(B\) is \(0.08~\text{V}.\) The speed \((v)\) of the rod is:
1. \(1\) m/s 2. \(2\) m/s
3. \(3\) m/s 4. \(4\) m/s
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A square loop of conducting wire \((PQRS)\) having \(100\) turns is placed in a uniform magnetic field \(B=10^{-3}~T,\) as shown in the figure. The square loop (of side: \(10~\text{cm}\)) rotates freely about the side \(PS,\) with a constant angular speed of \(100~\text{radian/s}.\) The ends of the wire are connected to the external points \(X,Y.\)
                                        
The emf induced across \(X,Y\) is:
1. an alternating square wave
2. an alternating triangular wave
3. a sinusoidal waveform
4. constant d.c.
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A metal wire of mass \(m\) slides without friction on two horizontal rails \(l\) distance apart. The track is in a vertical uniform magnetic field of induction \(B\). A battery of constant emf \(\varepsilon\) is connected to the rails. The terminal speed of the slider is:
1. \(\dfrac{\varepsilon{B}}{l}\) 2. \(\dfrac{\varepsilon}{Bl}\)
3. \(\dfrac{{3}\varepsilon}{2Bl}\) 4. \(\dfrac{{2}\varepsilon}{3Bl}\)
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A copper disc of radius \(0.1~\text{m}\) is rotated about its centre with \(20\) revolutions per second in a uniform magnetic field of \(0.1~\text{T}\) with its plane perpendicular to the field. The emf induced across the radius of disc is:
1. \(\frac{\mathit{\pi}}{20}\;~\text{V}\)
2. \(20\mathit{\pi}~\text{mV}\)
3. \({2}\mathit{\pi}\;~\text{mV}\)
4. \({20}\mathit{\pi}\;\mathit{\mu}\text{V}\)
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An infinitely long straight wire carrying current \(I\), one side opened rectangular loop and a conductor \(C\) with a sliding connector are located in the same plane, as shown in the figure. The connector has length \(l\) and resistance \(R\). It slides to the right with a velocity \(v\). The resistance of the conductor and the self inductance of the loop are negligible. The induced current in the loop, as a function of separation \(r\), between the connector and the straight wire is:

  
1. \( \frac{\mu_0}{\pi} \frac{I v l}{R r} \)
2. \( \frac{\mu_0}{2 \pi} \frac{I v l}{R r} \)
3. \(\frac{2 \mu_0}{\pi} \frac{I v l}{R r} \)
4. \( \frac{\mu_0}{4 \pi} \frac{I v l}{R r} \)

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A conducting rod moves in a uniform magnetic field as shown in the figure.
        
The induced EMF across the ends of the rod is:
1. \(3~\text{mV}\)
2. \(6~\text{mV}\)
3. \(0 ~\text{V}\)
4. \(1~\text{mV}\)
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Consider the following statements: 

(A) An emf can be induced by moving a conductor in a magnetic field.
(B) An emf can be induced by changing the magnetic field. 
 
1. Both A and B are True
2. A is True but B is False
3. B is True but A is False
4. Both A and B are False
Subtopic:  Motional emf |
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A conducting rod \(AB\) of length \(l=1~\text{m}\) is moving at a velocity \(2~\text{m/s}\) making an angle \(30^\circ\) with its length. A uniform magnetic field \( B=1~\text{T}\) exists in a direction perpendicular to the plane of motion. The emf induced across the rod is:

                
1. \(1~\text V\)

2. \(2~\text V\)

3. \(1.5~\text V\)

4. \(\dfrac43~\text V\)
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A metal rod of length \(1\) m is moving perpendicular to its length with \(8\) m/s velocity along the positive \(x\text-\)axis. A magnetic field \(B=2~\text{T}\) exists perpendicular to the plane of motion. The EMF induced between the two ends of the rod is:
1. \(16~\text{V}\) 
2. \(0~\text{V}\)
3. \(8~\text{V}\) 
4. \(4~\text{V}\)
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A rod of length \(l\) rotates with uniform angular velocity \(\omega\) about an axis passing through its one end and perpendicular to its length. If a uniform magnetic field exists perpendicular to the axis of rotation, then induced emf across the two ends of the rod is :
1. \(\dfrac{1}{2}B\omega l^2\)
2. \(B\omega l^2\)
3. \(2B\omega l^2\)
4. zero

Subtopic:  Motional emf |
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