Two equally charged, identical metal spheres A and B repel each other with a force 'F'. The spheres are kept fixed with a distance 'r' between them. A third identical, but uncharged sphere C is brought in contact with A and then placed at the mid-point of the line joining A and B. The magnitude of the net electric force on C is
(1) F
(2) 3F/4
(3) F/2
(4) F/4
1. | 9000 N9000 N | 2. | 12000 N12000 N |
3. | 24000 N24000 N | 4. | 36000 N36000 N |
A charge q is placed at the centre of the line joining two equal charges Q. The system of the three charges will be in equilibrium, if q is equal to
(1) −Q2−Q2
(2) −Q4−Q4
(3) +Q4+Q4
(4) +Q2+Q2
The figure shows the electric lines of force emerging from a charged body. If the electric fields at A and B are EA and EB respectively and if the distance between A and B is r, then:
1. EA > EBEA > EB
2. EA < EBEA < EB
3. EA = EBrEA = EBr
4. EA = EBr2EA = EBr2
ABCABC is an equilateral triangle. Charges +q+q are placed at each corner. The electric intensity at OO will be:
1. | 14πϵ0qr214πϵ0qr2 | 2. | 14πϵ0qr14πϵ0qr |
3. | zero | 4. | 14πϵ03qr214πϵ03qr2 |
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) mgemge
(3) emgemg
(4) e2m2ge2m2g
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
1. | σε0σε0 and is parallel to the surface |
2. | 2σε02σε0 and is parallel to the surface |
3. | σε0σε0 and is normal to the surface |
4. | 2σε02σε0 and is normal to the surface |
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