A system is shown in the figure. The time period for small oscillations of the two bolcks will be :-

Options

A. `100 Vm^(-1)` along X-axis
B. `100 Vm^(-1)` along Y-axis
C. `200 Vm^(-1)` at an angle `120^@` with X-axis
D. `50 Vm^(-1)` at an angle `120^@` with X-axis

Answer

C

Explanation

`dV = - vecE.dvecr`
`implies DeltaV =-E.Dletar cos theta`

`implies E=(-DeltaV)/(DeltarCos theta)=(-(20-10))/(10 xx10^(-2)cos 120^@)`
`implies E=(-10)/(10 xx10^(-2) xx((-1)/2))=200 V//m`
200V /m at an angle `120^@` with X-axis.