What is the result of an electric charge in uniform motion?

1. an electric field only.
2. a magnetic field only.
3. both electric and magnetic field.
4. neither electric nor magnetic field.

Subtopic:  Lorentz Force |
 81%
From NCERT
PMT - 1971
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The dots in the figure depict a magnetic field that is perpendicular to the plane of the paper and emanates from it. The trajectory of a particle in the plane of the paper is depicted by the curve \(ABC\). What exactly is the particle?

                            

1. Proton. 2. Electron.
3. Neutron. 4. It cannot be predicted.
Subtopic:  Lorentz Force |
 59%
From NCERT
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If an electron of velocity \(2\hat i +3\hat j\) is subjected to a magnetic field of \(4\hat{k}\):
1. the speed will change.
2. the direction will change.
3. both (1) and (2)
4. none of the above
Subtopic:  Lorentz Force |
 57%
From NCERT
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A particle of charge \(+q\) and mass \(m\) moving under the influence of a uniform electric field \(E\hat i\) and a uniform magnetic field \(\mathrm B\hat k\) follows a trajectory from \(P\) to \(Q\) as shown in the figure. The velocities at \(P\) and \(Q\) are \(v\hat i\) and \(-2v\hat j\) respectively. Which of the following statement(s) is/are correct?

       
1. \(E=\frac{3}{4} \frac{{mv}^2}{{qa}}\).
2. Rate of work done by electric field at \(P\) is \(\frac{3}{4} \frac{{mv}^3}{a}\).
3. Rate of work done by both fields at \(Q\) is zero.
4. All of the above.
Subtopic:  Lorentz Force |
 70%
From NCERT
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When a proton is released from rest in a room, it starts with an initial acceleration \(a_0\) towards the east. When it is projected towards the north with a speed of \(v_0\), it moves with an initial acceleration of \(3a_0\) towards the east. What are the electric and magnetic fields in the room?
1. \(\frac{M a_0}{e} ~\text{west,}~ \frac{M a_0}{e v_0}~\text{up}\)
2. \(\frac{M a_0}{e} ~\text {west,} ~\frac{2 M a_0}{e v_0}~\text{down}\)
3. \(\frac{M a_0}{e} ~\text{east,} \frac{2 M a_0}{e v_0}~\text{up}\)
4. \(\frac{M a_0}{e} ~\text {east,} \frac{3 M a_0}{e v_0} ~\text {down}\)

Subtopic:  Lorentz Force |
 56%
From NCERT
AIPMT - 2013
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When a positively charged particle moves in an \(x\text-y\) plane, its path abruptly changes due to the presence of electric and/or magnetic fields beyond \(P\). The curved path is depicted in the \(x\text-y\) plane and is discovered to be noncircular. Which of the following combinations is true?
          
1. \(\vec{{E}}=0 ; \vec{{B}}={b} \hat{i}+{c} \hat{k}\) 
2. \(\vec{E}={a\hat{i}} ; \vec{B}={c} \hat{k}+a\hat{i}\)
3. \(\vec{E}=0 ; \vec{B}=c \hat{j}+b \hat{k}\)
4. \(\vec{E}=a\hat i ; \vec{B}=c\hat{k}+{b}\hat{j}\)

Subtopic:  Lorentz Force |
 50%
From NCERT
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A charged particle is projected through a region in a gravity-free space. If it passes through the region with constant speed, then the region may have:
1. \(\vec{E}=0, \vec{B} \neq 0\)
2. \(\vec{E} \neq 0, \vec{B} \neq 0\)
3. \(\vec{E} \neq 0, \vec{B}=0\)
4. Both (1) & (2)

Subtopic:  Lorentz Force |
 62%
From NCERT
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A current-carrying wire is placed in a uniform magnetic field in the shape of the curve \(y= \alpha \sin \left({\pi x \over L}\right),~0 \le x \le2L.\) 
What will be the force acting on the wire?
                   

1. \(iBL \over \pi\) 2. \(iBL \pi\)
3. \(2iBL \) 4. zero
Subtopic:  Lorentz Force |
 69%
From NCERT
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A current \(I\) is carried by an elastic circular wire of length \(L\). It is placed in a uniform magnetic field \(B\) (out of paper) with its plane perpendicular to \(B'\text{s}\) direction. What will happen to the wire?

       

1. No force 2. A stretching force
3. A compressive force 4. A torque
Subtopic:  Current Carrying Loop: Force & Torque |
 52%
From NCERT
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A metallic rod of mass per unit length of \(0.5\) kgm–1 is lying horizontally on a smooth inclined plane which makes an angle of \(30^\circ\) with the horizontal. The rod is not allowed to slide down by flowing a current through it when a magnetic field of induction of \(0.25\) T is acting on it in the vertical direction. What is the current flowing through the rod to keep it stationary?
1. \(7.14\) A 2. \(5.98\) A
3. \(14.76\) A 4. \(11.32\) A
Subtopic:  Lorentz Force |
 57%
From NCERT
NEET - 2018
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