A hollow insulated conducting sphere is given a positive charge of 10μC. What will be the electric field at the centre of the sphere if its radius is 2 meters 

(1) Zero

(2) 5 μCm–2

(3) 20 μCm–2

(4) 8 μCm–2

Subtopic:  Electric Field |
 91%
From NCERT
PMT - 1998
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An electron of mass \(m_{e}\) initially at rest, moves through a certain distance in a uniform electric field in time \(t_{1}.\) A proton of mass \(m_{p}\) also initially at rest takes time \(t_{2}\) to move through an equal distance in this uniform electric field. The ratio of \(\frac{t_{2}}{t_{1}}\) is nearly equal to- (Neglect the effect of gravity.)

1. \(1\)
2. \(\left ( \frac{m_{p}}{m_{e}} \right )^{1/2}\)
3. \(\left ( \frac{m_{e}}{m_{p}} \right )^{1/2}\)
4. \(1836\)

Subtopic:  Electric Field |
 61%
From NCERT
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Point charges +4q, –q and +4q are kept on the x-axis at points x = 0, x = a and x = 2a respectively, then:

(1) only -q is in stable equilibrium.

(2) none of the charges are in equilibrium.

(3) all the charges are in unstable equilibrium.

(4) all the charges are in stable equilibrium.

Subtopic:  Coulomb's Law |
From NCERT
PMT - 1992
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Three identical positive point charges, as shown are placed at the vertices of an isosceles right-angled triangle. Which of the numbered vectors coincides in direction with the electric field at the mid-point \(M\) of the hypotenuse?
                 
1. \(1\)
2. \(2\)
3. \(3\)
4. \(4\)

Subtopic:  Electric Field |
 78%
From NCERT
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The figures below show regular hexagons, with charges at the vertices. In which of the following cases the electric field at the centre is not zero?

(1) 1

(2) 2

(3) 3

(4) 4

Subtopic:  Electric Field |
 74%
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An electron enters an electric field with its velocity in the direction of the electric lines of force. Then: 

1. the path of the electron will be a circle. 2. the path of the electron will be a parabola.
3. the velocity of the electron will decrease. 4. the velocity of the electron will increase.

Subtopic:  Electric Field |
 59%
From NCERT
PMT - 2000
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Two small spherical balls each carrying a charge Q = 10 μC (10 micro-coulomb) are suspended by two insulating threads of equal lengths 1m each, from a point fixed in the ceiling. It is found that in equilibrium threads are separated by an angle 60° between them, as shown in the figure. What is the tension in the threads (Given: 1(4πε0)=9×109Nm/C2) 

(1) 18 N

(2) 1.8 N

(3) 0.18 N

(4) None of the above

Subtopic:  Coulomb's Law |
 73%
From NCERT
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An electron having charge \(e\) and mass \(m\) is moving in a uniform electric field \(E.\) Its acceleration will be:
1. \(\frac{e^2}{m}\)
2. \(\frac{E^2e}{m}\)
3. \(\frac{eE}{m}\)
4. \(\frac{mE}{e}\)

Subtopic:  Electric Field |
 90%
From NCERT
AIIMS - 2002
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Infinite charges of magnitude q each are lying at x =1, 2, 4, 8... meter on X-axis. The value of the intensity of the electric field at point x = 0 due to these charges will be 

(1) 12 × 109q N/C

(2) Zero

(3) 6 × 109q N/C

(4) 4 × 109q N/C

Subtopic:  Electric Field |
 67%
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A pendulum bob of mass 30.7×106kg and carrying a charge 2×108C is at rest in a horizontal uniform electric field of 20000 V/m. The tension in the thread of the pendulum is (g=9.8m/s2)

(1) 3×104N

(2) 4×104N

(3) 5×104N

(4) 6×104N 

Subtopic:  Electric Field |
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