Question

In a parallel plate capacitor the separation between the plates is 3mm with air between them. Now a 1mm thick layer of a material of dielectric to the original value the separation between the plates must be made

• A. 1.5 mm
• B. 2.5 mm
• C. 3.5 mm
• D. 4.5 mm

Answer 1

The correct option is C

3.5 mm

$K=\frac{t}{t-d^{\prime }}\Rightarrow 2=\frac{1}{1-d^{\prime }}\Rightarrow d^{\prime }=\frac{1}{2}mm$

So, new distance $=3+\frac{1}{2}=3.5mm$