Question

In a vertical `U` - tube a column of mercury oscillates simple harmonically. If the tube contains `1kg` of mercury and `1cm` of mercury column weighs `20 g`, then the period of oscillation is
A. `1s`
B. `2 s`
C. `sqrt (2) s`
D. Insufficient data

Answer 1

Correct Answer - A
`T = 2pi sqrt ((l)/(g))`

`2l = (1000)/(20) g`
`= 50cm = 0.5 cm`
`rArr l = 0.25 m`
Now `T = 2pi sqrt ((0.25)/(9.8)) = 1 s`