Engineering Q&A
Define the following terms: 1) Virtual height 2) Actual height 3) Critical frequency. 4) Maximum usable frequency.
by

1 Answer

0 like 0 dislike

1) Virtual height:- The incident and refracted rays follow paths that are exactly the same as they have been if reflection had taken place from a surface located at a greater height, called Virtual height of this layer 


2) Actual height:- The actual height of the wave in the ionized layer is a curve and is due to refraction of wave. The height from this curve to earth surface is called actual height. 


3) Critical frequency: The critical frequency of a layer is defined as the maximum frequency that is returned back to the earth by that layer, when the wave is incident at an angle 900 (normal) to it. The critical frequency for F2 layer is between 5 to 12 MHz. 


4) Maximum usable frequency: The limiting frequency when the angle of incidence is other than the normal is known as maximum unstable frequency. MUF= fc secθ 

by

Related questions

1 answer
Welcome to electronics2electrical.com, where students and teachers can ask and answer any question. Get help and answers to any engineering problem including Electrical, electronics, mechanical, telecommunication, instrumentation, computer, mathematics, physics etc. Get answers to questions. Help is always 100% free!

Most popular tags

power motor dc circuit transformer voltage current system used phase resistance factor ac load synchronous induction energy electric generator electrical series frequency capacitor between plant line speed transmission use meter type advantages difference single mosfet control function instrument problem magnetic diode amplifier high bjt machine unit source motors and diagram winding shunt field parallel define electricity torque value maximum time relay types arduino supply digital armature applications thyristor working transformers wave on flow operation three coil material instruments state ratio signal emf effect formula efficiency theorem method disadvantages starting microprocessor network test operating direction controlled different logic transistor single-phase scr loss temperature connected rc law force inductance compare measure station wire low conductor principle wattmeter full characteristics measuring constant measurement breaker losses device converter bridge linear materials nuclear matrix flux drive resistivity of machines angle switch free rectifier protection core circuits battery solar gain thermal loop generators open negative analog number lines friction basic reactance short gate pole inverter the conservation diesel iron resistors capacitance engineering using direct main electronic electronics a steam induced relays hysteresis universal transducer computer feedback range distribution work secondary igbt algebra pmmc plants factors capacitors dielectric controller regulation systems design air fault components rotor cable starter oscillator eddy alternator application semiconductor ammeter rl average forces damping rlc connection zener electromagnetic biasing minimum insulation pressure balanced permanent moving errors running copper self analysis impedance stability quality start ideal curve over commutation is 3-phase arc permeability peak bias error fuzzy commutator conductors superposition density mechanical rotation construction measured electrons charge memory inductive two transfer explain fuse methods off back three-phase tariff locomotive installation welding heating rms surge rating generation potentiometer coupled shaded rate capacity storage adc excitation active pure resistor harmonics reluctance microcontroller voltmeter inductor internal 8085 cro reaction insulating overhead hydro resonance traction definition breakers earth

9,199 questions

7,948 answers

158 comments

3,292 users

9,199 questions
7,948 answers
158 comments
3,292 users