Consider the broadcasting circuit for an AM radio station which broadcasts at a

Question

Consider the broadcasting circuit for an AM radio station which broadcasts at a frequency of 1400 kHZ. The free electrons in such a circuit are moving back and forth in simple harmonic motion. Assuming the average speed of the electrons is 100 um/s, what is the range of motion of the electrons as they go back and forth in the wires of the circuit. (hint: this is two part problem; first find the time for an electron to go back and forth once; then as it travels its full range every half cycle) Part II: what is the wavelength of the elctromagnetic radio waves emitted by this broadcsting circuit?

Explanation / Answer

i)

given

frequency, f = 1400 kHz = 1.4*10^6 hz

average speed, v_avg = 100 micro m/s = 1*10^-4 m/s

time period, T = 1/f

= 1/(1.4*10^6)

= 7.14*10^-7 s

range of electron = v_avg*T/2

= 1.4*10^6*(7.14*10^-7/2)

= 0.5 m

ii) apply, c = lamda*f

lamda = c/f

= 3*10^8/(1.4*10^6)

= 214.2 m

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.