Class 11th

The height 'h' at which the weight of a body will be the same as that at the same depth 'h' from the surface of the earth is (Radius of the earth is R and effect of the rotation of the earth is neglected)

Let S be the sum of the first 9 terms of series (x+ka)+(x²+(k+2)a)+(x³+(k+4)a)+(x?+(k+6)a)+., where a≠0 and x≠1. If S=(x¹?-x+45a(x-1))/(x-1), then k is equal to

In a hydrogen atom, an electron makes a transition from (n + 1)th level to the nth level. If n >> 1, the frequency of radiation emitted is proportional to:

The number of sequences of ten terms, whose terms are either 0 or 1 or 2, that contain exactly five 1s and exactly three 2s, is equal to

In the following, digital circuit, what will be the output at ' Z ', when the input (A, B) are (1,0), (0,0), (1,1), (0,1)

A charge Q is distributed over two concentric conducting thin spherical shells of radii r and R (R > r). If the surface charge densities on the two shells are equal, the electric potential at the common centre is: