Answer :
The capacity increases and potential decreases with the introduction of dielectric .
Explanation:
The capacity of parallel plate capacitor when air is in between
C₀ = ε₀A/d
and when dielectric is introduced
The capacity C = Kε₀A/d
where K is dielectric constant .
When dielectric is introduced between the parallel plate capacitor , its capacity increases .
If the capacity of capacitor is C₀ initially . It will be 3 C₀ , after introducing the dielectric .
Thus if the initial potential V₀ = [tex]\frac{Q_0}{C_0}[/tex] , the potential with dielectric is = [tex]\frac{Q_0}{3C_0}[/tex]
Thus the potential will become become 1/3 of initial value .
and the capacitance becomes 3 times the initial value .