Question 3.
- List five classes of electromagnetic spectrum with respect to radio wave propagation.
- State the frequency band for each of the classes listed in 3(a)Works workshop.
- For a series RLC circuit, derive an expression for its resonant frequency.
Observation
The expected answers were:
Electromagnetic Spectrum for Radio Propagation
(a) Class |
(b) |
Low frequency LF |
30kHz – 300kHz |
Medium Frequency MF |
300kHz - 3MHz |
High Frequency HF |
3MHz – 30MHz |
Very High Frequency VHF |
30MHz – 300MHz |
Ultra High Frequency UHF |
300MHz – 3GHz |
Super High Frequency SHF |
3GHz – 30GHz |
Extra High Frequency EHF |
30GHz – 300GHz |
at resonance, 
By definition;
then, 
The question was on Electronic Communication System. It was poorly answered by candidates.