A simple pendulum has time period `T` The bob is given negative charge and surface below it is given positive change new time period will be

Options

A. Infinite
B. Equal to T
C. Greater than T
D. Less than T

Answer

D

Explanation

There will be an electrostatic force of attraction `(F_(e ))` between the bob and the surface. If m is the mass of the bob, then the resul"tan"t downward force acting on the bob is `F=mg +F_(e )`

`therefore ` as the force is increased, the effective value of g is also increased and
`because T prop sqrt((l)/(g)) therefore T' lt T`