Q. No.If a charge '\(q\)' moves with velocity \(v\), in a region where electric field (\(E\)) and magnetic field (\(B\)) both exist, then force on it is:
1. \(q(\vec{v} \times \vec{B})\)
2. \(q \vec{E}+{q}(\vec{v} \times \vec{B})\)
3. \( q \vec{E}+q(\vec{B} \times \vec{v})\)
4. \(q\vec{B}+{q}(\vec{E} \times \vec{v})\)
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1. \( 3\times 10^{-4}~\text{N}\)
2. \(3\sqrt2\times10^{-5}~\text{N}\)
3. \(3\times10^3~\text{N}\)
4. zero
A proton carrying 1 MeV kinetic energy is moving in a circular path of radius R in a uniform magnetic field. What should be the energy of an -particle to describe a circle of the same radius in the same field?
1. 2 MeV 2. 1 MeV
3. 0.5 MeV 4. 4 MeV
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1. \(3\)
2. \(6\)
3. \(12\)
4. \(2\)
| 1. | a magnet |
| 2. | an unmagnetised iron bar |
| 3. | a moving charge |
| 4. | stationary charge |
What is the magnitude of magnetic force per unit length on a wire carrying a current of \(8~\text{A}\) and making an angle of \(30^{\circ}\) with the direction of a uniform magnetic field of \(0.15~\text{T}?\)
| 1. | \(0.04~\text{N/m}\) | 2. | \(0.6~\text{N/m}\) |
| 3. | \(1.5~\text{N/m}\) | 4. | \(0.33~\text{N/m}\) |
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| 1. | \(ILB\) | 2. | \(ILB\cos30^\circ\) |
| 3. | \(ILB\sin30^\circ\) | 4. | \(ILB\tan30^\circ\) |
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A uniform electric field and a uniform magnetic field are acting in the same direction in a certain region. If an electron is projected in the region such that its velocity is pointed along the direction of fields, then the electron :
1. speed will decrease
2. speed will increase
3. will turn towards the left of the direction of motion
4. will turn towards right of direction a motion
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| 1. | \(\text{Current}\) | 2. | \(\dfrac{\text{Current}}{\text{Length}}\) |
| 3. | \(\text{Current}\times\text{Length}\) | 4. | \(\dfrac{\text{Current}}{\text{Area}}\) |
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Consider three quantities; \(x = E/B,\) \(y = \sqrt{1 / \mu_{0} \varepsilon_{0}},\) and \(z=\frac{ l }{ CR}.\) Here, \(l\) is the length of a wire, \(C\) is a capacitance and \(R\) is resistance. All other symbols have standard meanings.
| (a) | \(x\) and \(y\) have the same dimensions. |
| (b) | \(y\) and \(z\) have the same dimensions. |
| (c) | \(z\) and \(x\) have the same dimensions. |
| (d) | None of the three pairs have the same dimensions. |
Choose the correct option from the given ones.
| 1. | (a), (b), and (c) only |
| 2. | (b) and (c) only |
| 3. | (c), (d), and (b) only |
| 4. | (a), (d), and (c) only |
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