Two simple pendulums have time periods T and `(5T)/(4)`. They start vibrating at the same instant from the mean position in the same phase. The phase difference between them when the bigger pendulum completes one oscillation will be

Options

A. `90^(@)`
B. `60^(@)`
C. `45^(@)`
D. `30^(@)`

Answer

A

Explanation

When B completes one oscillation in time `(5T)/(4)`, A will complete `(5)/(4)` oscillations i.e. Pendulum A will be ahead of B by `(1)/(4)` oscillation. `(1)/(4)` oscillation corresponds to `(T)/(4)` or a path difference of `(lamda)/(4)` or a phase difference of `(pi)/(2)` radian or `90^(@)`.