Question

An air capacitor is connected to a battery. The effort of filling the space between the plates with a dielectric is to increase

• A. the electric field and the capacitance
  
• B. the potential difference and the electric field
  
• C. the charge and the capacitance
• D. the charge and the potential difference
  

Answer 1

The correct option is C

the charge and the capacitance

charge on capacitor $Q=CV$ , where $V=$ potential difference .

After inserting dielectric slab capacitance of system will increase
( After inserting dielectric of dielectric constant $k$, capacitance becomes $kC$ where $k>1$).

Voltage is constant as the battery remains connected .

So, the charge will increase. Thus, dielectric is placed to increase charge and capacitance.

Hence, correct option is (D)