Radio,Television And Electronic Paper 2, May/June 2015

Question 3.

  1. List five classes of electromagnetic spectrum with respect to radio wave propagation.
  2. State the frequency band for each of the classes listed in 3(a)Works workshop.
  3.   For a series RLC circuit, derive an expression for its resonant frequency.


The expected answers were:
Electromagnetic Spectrum for Radio Propagation


Frequency band


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;


The question was on Electronic Communication System. It was poorly answered by candidates.