A parallel plate condenser is filled with two dielectrics as shown in figure. Area of each pate is $A \mathrm{~m}^2$ and the separation is $d$ metre. The dielectric constants are $K_1$ and $K_2$ respectively. Its capacitance in farad will be

• A

  $\frac{2 \varepsilon_0 A}{d}\left(\frac{K_1+K_2}{K_1 K_2}\right)$
• Correct answer
  B

  $\frac{2 \varepsilon_0 A}{d}\left(\frac{K_1 K_2}{K_1+K_2}\right)$
• C

  $\frac{\varepsilon_0 A}{d}\left(\frac{K_1+K_2}{2 K_1 K_2}\right)$
• D

  $\frac{\varepsilon_0 A K_1 K_2}{2\left(d_2 K_1+d_1 K_2\right)}$

Hence, the correct answer is option: 'B'.