Case : Read the passage and answer the question(s).

In a parallel plate air capacitor having plate separation 0.05mm, an electric field of 4X10⁴ V/m is established between the plates. After the removal of the battery a metal plate of thickness t = 0.02 mm is inserted between the plates of the capacitor. 

What is the potential difference across capacitor before the introduction of metal plates?

2000 V

V = E x d 

E = 4X10⁴ V/m ; d = 0.05mm

V = 2000 V