\(ABC\) is an equilateral triangle. Charges \(+q\)  are placed at each corner. The electric intensity at \(O\) will be: 

       

1.	\(\dfrac{1}{4\pi\epsilon _0}\dfrac{q}{r^{2}}\)	2.	\(\dfrac{1}{4\pi\epsilon _0}\dfrac{q}{r^{}}\)
3.	zero	4.	\(\dfrac{1}{4\pi\epsilon _0}\dfrac{3q}{r^{2}}\)

The magnitude of electric field intensity E is such that, an electron placed in it would experience an electrical force equal to its weight is given by 

(1) mge

(2) $\frac{mg}{e}$

(3) $\frac{e}{mg}$

(4) $\frac{e^2}{m^2}g$

A charge particle is free to move in an electric field. It will travel 

(1) Always along a line of force

(2) Along a line of force, if its initial velocity is zero

(3) Along a line of force, if it has some initial velocity in the direction of an acute angle with the line of force

(4) None of the above

An uncharged sphere of metal is placed in between two charged plates as shown. The lines of force look like 

(1) A

(2) B

(3) C

(4) D

The magnitude of electric field E in the annular region of a charged cylindrical capacitor 

(1) Is same throughout

(2) Is higher near the outer cylinder than near the inner cylinder

(3) Varies as 1/r, where r is the distance from the axis

(4) Varies as 1/r², where r is the distance from the axis

A metallic solid sphere is placed in a uniform electric field. The lines of force follow the path(s) shown in figure as 

(1) 1

(2) 2

(3) 3

(4) 4

The figure shows some of the electric field lines corresponding to an electric field. The figure suggests 

(1) E_A > E_B > E_C

(2) E_A = E_B = E_C

(3) E_A = E_C > E_B

(4) E_A = E_C < E_B

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

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. \(1836\)