# A wooden block perform SHM on a frictionless surface with frequency ν0. The block carries a charge +Q on its surface…

Q: A wooden block perform SHM on a frictionless surface with frequency ν0. The block carries a charge +Q on its surface. If now a uniform electric field $\vec{E}$ is switched-on as shown, then the SHM of the block will be

(a)Of the same frequency and with shifted mean position

(b)Of the same frequency and with same mean position

(c)Of the changed frequency and with shifted mean position

(d)Of the changed frequency and with same mean position

Ans: (a)

Sol: As constant external force can only change the mean position . When electric field is switched on , mean position will be obtained after a compression of x0

$\large k x_0 = Q E$

$\large x_0 = \frac{Q E}{k}$