The fundamental frequency of an air column in pipe 'A' closed at one end coincides with second overtone of pipe 'B' open at both ends. The ratio of length of pipe 'A' to that of pipe 'B' is
An electron is projected along the axis of circular conductor carrying current '$$\mathrm{I}$$' The electron will experience
A thin ring of radius '$$R$$' meter has charge '$$q$$' coulomb uniformly spread on it. The ring rotates about its axis with a constant frequency of $$f$$ revolution/s. The value of magnetic induction in $$\mathrm{Wb} \mathrm{m}^{-2}$$ at the center of the ring is ($$\mu_0=$$ Permeability of free space)
A charged spherical conductor has radius '$$r$$'. The potential difference between its surface and 3 point at a distance '$$3 r$$' from the centre is '$$v$$' The electric intensity at a distance '$$3 r$$' from the centre of the conductor is