The temperature of a black body is increased by $$50 \%$$, then the percentage increase in the rate of radiation by the body is approximated

A particle excuting S.H.M starts from the mean position. Its amplitude is 'A' and time period '$$\mathrm{T}$$' At what displacement its speed is one-fourth of the maximum speed?

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