question_answer

A parallel plate capacitor has two square plates with equal and opposite charges. The surface charge densities on the plates are + \[\sigma \] and - \[\sigma \] respectively. In the region between the plates the magnitude of the electric field is

A)                 \[\frac{\sigma }{2{{\varepsilon }_{0}}}\]                                

B) \[\frac{\sigma }{{{\varepsilon }_{0}}}\]

C)                  zero                                     

D)  None of these

Correct Answer: B

Solution :

                  The magnitude of the electric field \[E=\frac{1}{2{{\varepsilon }_{0}}}[\sigma -(-\sigma )]\] \[E=\frac{2\sigma }{2{{\varepsilon }_{0}}}\] \[E=\frac{\sigma }{{{\varepsilon }_{0}}}\]