LC circuits may be used as a part of a radio to emit or receive electromagnetic
ID: 3900773 • Letter: L
Question
LC circuits may be used as a part of a radio to emit or receive electromagnetic waves. Consider an LC oscillator circuit with L = 1.9 ?H and C = 65 pF that is part of a shortwave radio station transmitter.
a) What is the wavelength of electromagnetic waves broadcast?
b) You want to double the wavelength by changing the capacitance in the oscillator circuit. What is the new capacitance?
c) At a particular location and time, the electric field of the wave points west and the magnetic field of the wave points up. What is the direction of travel of the wave? Possible options are: up, down, north, south , east , west.
d) At a particular location and time, the wave is traveling to the west and the magnetic field of the wave points down. What is the direction of the electric field? Possible options are: up, down, north, south , east , west.
Explanation / Answer
a)
f = 1/(2*pi*sqrt(L*C))
= 1/(2*3.14*sqrt(1.9*10^-6*65*10^-12))
= 1.433*10^7 Hz
we know, c = lamda*f
==> lamda = c/f = 3*10^8/1.433*10^7 = 20.935 m
b) lamda' = 2*lamda
==> f' = f/2
==> C' = 4*C = 4*65*10^-12 = 260 pF
c) North
d) south
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.