An observer heard the sound of thunder 5.8s after the lightning flash was seen. How far was he from the source? [Speed of sound in air = 330ms-1]
Which of the following substances undergoes sublimation?
Determine the value of x from the nuclear reaction below,
\(^{222}_{86}Rn\) → \(^{x}_{88}Ra\) + 2β + energy
