A rod of length \(L\) rotates with a small uniform angular velocity \(\omega\) about its perpendicular bisector. A uniform magnetic field \(\mathrm B\) exists parallel to the axis of rotation. The potential difference between the centre of the rod and an end is:
1. \(\large\frac{B\omega L^2}{8}\)
2. \(\large\frac{B\omega L^2}{2}\)
3. \(\large\frac{B\omega L^2}{4}\)
4. zero
Subtopic:  Motional emf |
From NCERT
NEET - 2024
Please attempt this question first.
Hints
Please attempt this question first.

An emf is generated by an ac generator having \(100\) turn coil, of loop area \(1\) m2. The coil rotates at a speed of one revolution per second and placed in a uniform magnetic field of \(0.05\) T perpendicular to the axis of rotation of the coil. The maximum value of emf is:
1. \(3.14\) V
2. \(31.4\) V
3. \(62.8\) V
4. \(6.28\) V
Subtopic:  Motional emf |
 71%
From NCERT
NEET - 2023
Please attempt this question first.
Hints
Please attempt this question first.

A wheel with \(20\) metallic spokes, each \(1\) m long, is rotated with a speed of \(120\) rpm in a plane perpendicular to a magnetic field of \(0.4~\text{G}\). The induced emf between the axle and rim of the wheel will be:
\((1~\text{G}=10^{-4}~\text{T})\)
1. \(2.51 \times10^{-4}\) V
2. \(2.51 \times10^{-5}\) V
3. \(4.0 \times10^{-5}\) V
4. \(2.51\) V

Subtopic:  Motional emf |
 60%
From NCERT
NEET - 2020
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
Links
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

advertisementadvertisement

A cycle wheel of radius \(0.5\) m is rotated with a constant angular velocity of \(10\) rad/s in a region of a magnetic field of \(0.1\) T which is perpendicular to the plane of the wheel. The EMF generated between its centre and the rim is:

1. \(0.25\) V 2. \(0.125\) V
3. \(0.5\) V 4. zero
Subtopic:  Motional emf |
 68%
From NCERT
NEET - 2019
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
Links
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

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:


     
1. \( \frac{1}{x^2} \)
2. \( \frac{1}{(2 x-a)^2} \)
3. \( \frac{1}{(2 x+a)^2} \)
4. \(\frac{1}{(2 x-a)(2 x+a)}\)

Subtopic:  Motional emf |
 72%
From NCERT
NEET - 2015
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
Links
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

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
Subtopic:  Motional emf |
 74%
From NCERT
AIPMT - 2014
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
Links
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

advertisementadvertisement

A rectangular, a square, a circular, and an elliptical loop, all in the \((x\text-y)\) plane, are moving out of a uniform magnetic field with a constant velocity, \(\vec{v}= v\hat{i}.\) The magnetic field is directed along the negative \(z\text-\)axis direction. The induced emf, during the passage of these loops out of the field region, will not remain constant for:
1. the rectangular, circular, and elliptical loops.
2. the circular and the elliptical loops.
3. only the elliptical loop.
4. any of the four loops.
Subtopic:  Motional emf |
 72%
From NCERT
AIPMT - 2009
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
Links
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

Initially plane of a coil is parallel to the uniform magnetic field \(B\). If in time \(\Delta t\) the coil is perpendicular to the magnetic field, then charge flows in \(\Delta t\) depends on this time as:
1. \(\propto \Delta t\)
2. \(\propto \frac{1}{\Delta t}\)
3. \(\propto (\Delta t)^0\)
4. \(\propto (\Delta t)^{2}\)

Subtopic:  Motional emf |
 77%
From NCERT
AIPMT - 1999
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
Links
To view explanation, please take trial in the course.
NEET 2025 - Target Batch