Question

Two identical particles of charge q each are connected by a mass less spring of force constant K. They are placed over a smooth horizontal surface.They are released when the separation between them is r and spring is in its natural length. If maximum extension of the spring is r, the value of K is:
(neglect gravitational effect)

• A. $\frac{q}{4r}\sqrt{\frac{1}{\pi {ϵ}_{0}r}}$
• B. $\frac{q}{2r}\sqrt{\frac{1}{\pi {ϵ}_{0}r}}$
• C. $\frac{k{r}^2}{2}$
• D. $\frac{q}{r}\sqrt{\frac{1}{\pi {ϵ}_{0}r}}$

Answer 1

The correct option is B $\frac{q}{2r}\sqrt{\frac{1}{\pi {ϵ}_{0}r}}$