Question

The bob of a pendulum of mass `8 mu g` carries an electric charge of `39.2xx10^(-10)` coulomb in an electric field of `20xx10^(3)` volt/meter and it is at rest. The angle made by the pendulum with the vertical will be
A. `27^(@)`
B. `45^(@)`
C. `87^(@)`
D. `127^(@)`

Answer 1

Correct Answer - b
`T sin theta= qE, T cos theta= mg`

`:. tan theta= (qE)/(mg)= (39.2xx10^(-10)xx20xx10^(3))/(8xx10^(-6)xx9.8)=1`
`implies theta= 45^(@)`