A voltmeter reads 4 V when connected to a parallel plate capacitor with air as a dielectric. When a dielectric slab is introduced between plates for the same configuration , voltmeter reads 2V. What is the dielectric constant of the material ?

Options

A. 8
B. 0.5
C. 10
D. 2

Answer

D

Explanation

Let `V_(0)` be the potential difference between the plantes of an air filled paralled plate capacitor. When a dielectric slab is introduced between its plates, its potential difference will become
`V=(V_(0))/(K)`
where K is the dielectric constant of the slab.
`:.K=(V_(0))/(V)`
Here, `V_(0)=4V, V=2V`
`:.K=(4V)/(2V)=2`