Question

Two capacitors are same except one is filled with oil and other is filled with air both have same charges what is the ratio of electric field from air to oil?

Answer 1

oils have dielectric constants that typically range from 2.1 to 2.4 lets assume this as 'k'

Capacitance hence will become 'kC' , where C is capacitance of the capacitor in air

So we have two capacitors one with capacitance 'kC' and the other one with the capacitance 'C'

As we know that $q=CV$

As the both the capacitance are carrying equal charges we can write it as

$CV_{air}=kCV_{oil }\\\frac{V_{air}}{V_{oil}}=k$

As electric field in capacitor is given by the V/d and here d is same in both the capacitor

Hence the ratio of Electric field will be same as that of Voltage

$\frac{E_{air}}{E_{oil}}=k$