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

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. \(1836\)