Question

A capacitor of capacitance $5\mu F$ is connected to a battery of emf $4\text{V}.$ Now this charged capacitor is disconnected with the battery and a dielectric of dielectric constant $2$ is inserted between the plates. Find the magnitude of the charge induced on each surface of dielectric

• A. $0\mu C$
• B. $10\mu C$
  
• C. $20\mu C$
  
• D. $40\mu C$
  

Answer 1

The correct option is B $10\mu C$


Charge stored on the capacitor,
$Q=CV$
$\Rightarrow Q=5\times 4=20\mu F$
Now when dielectric is inserted , induced charge is given as,
$Q^1=Q(1-\frac{1}{K})$
$\Rightarrow Q^1=20(1-\frac{1}{2})$
$\therefore Q^1=10\mu C$