Two large insulating plates having surface charge densities $+\mathrm{ }\mathrm{\sigma }$ and $–\mathrm{\sigma }$ are fixed at a distance $\mathrm{d}$ from each other. A small test charge $\mathrm{q}$ of mass $\mathrm{m}$ is attached to two identical springs as shown in the figure. The charge $\mathrm{q}$ is now released from rest with springs in natural length. Then $\mathrm{q}$ will (neglect gravity)