Question

An air capacitor is charged up to potential V₁. It is connected in parallel to an identical uncharged capacitor filled with a dielectric medium. After redistribution of charge is final potential difference of this combination is V, then the dielectric constant of the substance will be – (Both the capacitors with air medium has same capacitance)

• A. V² (V₁ – V)
• B. V (V₁ – V)
• C. V/(V₁ – V )
• D. (V₁ – V)/ V

Answer 1

Answer: (D)

(V₁ – V)/ V

Answer 2

V = $\frac { \mathrm { q } _ { 1 } + \mathrm { q } _ { 2 } } { \mathrm { C } _ { 1 } + \mathrm { C } _ { 2 } }$

V =

\ CV + KCV = CV₁

or K = $\frac { \mathrm { CV } _ { 1 } - \mathrm { CV } } { \mathrm { CV } }$

\ K = $\frac { V _ { 1 } - V } { V }$