# Objective Questions on Waveguide Posted by

## Objective Questions on Waveguide

Objective Questions on Waveguide, waveguide questions and answers, MCQ on waveguides, gate questions on rectangular waveguide, MCQ on rectangular and circular waveguide.

### Multiple Choice Questions

1. The waves in a waveguide
• travel along the border walls of the waveguide
• are reflected from the side walls but do not travel along them
• travel through the dielectric without touching the walls
• travel along all the four walls

Answer: travel along the border walls of the waveguide

2. Waveguides can carry

• TE mode
• TM mode
• mixed mode
• all

3. The cut-off frequency of a waveguide depends on

• dimensions of the waveguide
• wave mode
• the dielectric property of the medium in the waveguide
• all

4. In Rectangular Waveguide (RWG), the mode subscripts m and n indicate

• no. of half-wave patterns
• no. of full-wave patterns
• no. of the zeros of the field
• none

5. Wave impedance of waveguides in the TE mode can be

• $\frac{\eta }{\sqrt{1-(\frac{\lambda }{\lambda _{0}})^{2}}}$
• $\eta \sqrt{1-(\frac{\lambda }{\lambda _{0}})^{2}}$
• both
• none

Answer: $\frac{\eta }{\sqrt{1-(\frac{\lambda }{\lambda _{0}})^{2}}}$

6. The dominant TE mode in rectangular waveguides is

• TE01
• TE11
• TE20
• TE10

7. Cut-off wave length of rectangular waveguides is

• $\frac{2}{\sqrt{(\frac{m}{a})^{2}+(\frac{n}{b})^{2}}}$
• $\frac{2}{\sqrt{(\frac{m}{a})^{2}-(\frac{n}{b})^{2}}}$
• both
• none

Answer: $\frac{2}{\sqrt{(\frac{m}{a})^{2}+(\frac{n}{b})^{2}}}$

8. In RWG, for dominant mode, the cut-off wave length is

• 2a
• 2b
• a
• none

9. An air-filled rectangular waveguide has dimensions of 6 × 4 cm. Its cut-off frequency for the TE10 mode is

• 2.5 GHz
• 25 GHz
• 25 MHz
• 5 GHz

10. In hollow rectangular waveguides,

• the phase velocity is greater than the group velocity
• the phase velocity is greater than the velocity of light in free space
• both
• none

11. The dominant mode in the circular waveguide is

• TE10
• TE11
• TE01
• TE12

12. Nonexistent modes in circular waveguides are

• TE10
• TE00
• both
• none

13. Degenerate modes in circular waveguides are

• TE01 and TM11
• TE22 and TM22
• both
• none

14. Theoretically, the number of modes that can exist in cylindrical waveguides are

• zero
• one
• two
• infinite

• $\frac{\lambda}{\sqrt{1-(\frac{\lambda}{\lambda _{0}})^{2}}}$
• $\frac{\lambda}{\sqrt{1-(\frac{f_{0}}{f})^{2}}}$