Question

Direction: Question consists of two statements, one labelled as the 'Assertion (A)' and the other as 'Reason (R)'. Examine these two statements carefully and select the answer to this question using the codes given below:

Assertion (A): TEM (Transfer Electro-Magnetic) waves cannot propagate within a hollow waveguide of any shape.

Reason (R): For a TEM wave to exist within the waveguide, lines of the H field must be closed loops that require an axial component of E which is not present in a TEM wave.

1. Both A and R are individually true and R is the correct explanation of A
2. Both A and R are individually true but R is not the correct explanation of A
3. A is true but R is false
4. A is false but R is true

Answer 1

Correct Answer - Option 2 : Both A and R are individually true but R is not the correct explanation of A

Assertion Explanation-

The transmission line which consists of two or more conductors can support TEM propagation.

Since a Hollow waveguide of any shape made up of a single conductor so it can’t support TEM propagation. The assertion is the correct statement.

Reason Explanation-

According to the second boundary condition for a varying magnetic field to exist, it must form closed loops in parallel with the conductors and be perpendicular to the electric field.

So in any mode, TE/TM/TEM  lines of the H field must be closed.

Both statement is correct but R is not the correct explanation of A.