Question

3. A capacitor consists of two metal plates each 10 cm by 20 cm; they are separated by a 2.0 mm thick insulatorwith dielectric constant 4.1 and dielectric strength 6.0 x 107 V/m. What is the capacitance in PF (10-12F)?(1) 75DU (2) 100E KA DV(3) 240(4) 360​

Answer 1

Answer: (4) 360pF

Explanation:

We have a capacitor in which dielectric is inserted with dielectric constant 4.1.

Note that, inserting dielectric increases the capacitance.

Area of capacitor plate = 20cm *10cm

=200*10^(-4) = 0.02 m^2

Distance between plates = 2mm = 0.002m

Dielectric constant, k = 4.1

We know,

Capacitance is given by

$C=\frac{k\varepsilon_oA}{d}\\ \\=\frac{4.1*8.55*10^{-12}*0.02}{0.002}\\ \\=\frac{4.1*8.85*10*10^{-12}}{1} \\ \\=360 pF$