Question

The total permittivity of a dielectric transformer oil (relative permittivity is 2.2) will be (in order 10^-11)

(a) 1.94

(b) 19.4

(c) 0.194

(d) 194

This question was addressed to me during an online exam.

The origin of the question is Plane Waves in Dielectrics topic in division EM Wave Propagation of Electromagnetic Theory

Answer 1

Correct answer is (a) 1.94

Easy explanation: The total permittivity is the product of the absolute and the relative permittivity. The absolute permittivity is 8.854 x 10^-12 and the relative permittivity(in this case for transformer oil) is 2.2. Thus the total permittivity is 8.854 x 10^-12 x 2.2 = 1.94 x 10^-11 units.