Two spheres A and B of radius 'a' and 'b' respectively are at same electric potential. The ratio of the surface charge densities of A and B is
(a) `a/b`
(b) `b/a`
(c) `a^2/b^2`
(d) `b^2/a^2`

Two spheres of radius a and b respectively are charged and joined by a wire. The ratio of electric field of the spheres is

(a) a^2+b^2 (b) a+b (c) a^2-b^2 (d) sqrt(a^2+b^2)

Two isolated charged conducting spheres of radii a and b produce the same electric field near their surface. The ratio of electric potentials on their surfaces is

Two conducting concentric, hollow spheres A and B have radii a and b respectively, with A inside B. Their common potentials is V. A is now given some charge such that its potential becomes zero. The potential of B will now be

The ratio of the total surface area of a sphere and a hemisphere of same radius is 2:1 (b) 3:2 (c) 4:1 (d) 4:3

Three concentric spherical metallic spheres A,B and C of radii a , b and c(a lt b lt c) have surface charge densities sigma , -sigma and sigma respectively.

Two planets A and B have the same material density. If the radius of A is twice that of B, then the ratio of the escape velocity V_(A)//V_(B) is

In Q. No 126, c= (a) b (b) 2b (c) 2b^2 (d) -2b

Two parallel lines lying in the same quadrant make intercepts a and b on x and y axes, respectively, between them. The distance between the lines is (a) (ab)/sqrt(a^2+b^2) (b) sqrt(a^2+b^2) (c) 1/sqrt(a^2+b^2) (d) 1/a^2+1/b^2

Three concentric spherical metallic shells A, B, and C of radii a,b, and c(a lt b lt c) have surface charge densities sigma, -sigma and sigma , respectively. If V_(A), V_(B) and V_(C) are potential of shells A, B and C, respectively, match the columns {:("Column A",,,"Column B"),(a. V_(A),,i.,sigma/epsilon_(0)[(a^(2)-b^(2)+c^(2))/c]),(b. V_(B),,ii.,sigma^(2)/epsilon_(0)[a^(2)/b-b+c]),(c. V_(C),,iii.,sigma/epsilon_(0)[a-b+c]):}