# Objective Questions on Waveguide

## Objective Questions on Waveguide

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

### Multiple Choice Questions

Q.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

Q.2. Waveguides can carry

• TE mode
• TM mode
• mixed mode
• all

Q.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

Q.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

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

Q.6. The dominant TE mode in rectangular waveguides is

• TE01
• TE11
• TE20
• TE10

Q.7. Cut-off wavelength 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: $\frac{2}{\sqrt{(\frac{m}{a})^{2}+(\frac{n}{b})^{2}}}$

Q.8. In RWG, for dominant mode, the cut-off wavelength is

• 2a
• 2b
• a
• none

Q.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

Q.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

Q.11. The dominant mode in the circular waveguide is

• TE10
• TE11
• TE01
• TE12

Q.12. Nonexistent modes in circular waveguides are

• TE10
• TE00
• both
• none

Q.13. Degenerate modes in circular waveguides are

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

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

• zero
• one
• two
• infinite

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