Question

(a) Calculate the range of wavelengths (in m) for AM radio given its frequency range is 540 to 1,600 kHz. smaller value larger value

Answer 1

(a) we know

wavelength * frequency = speed

radio waves move at speed of light

so,

wavelength = speed / frequency

small wavelength = 3e8 / 1600,000 = 188 m

larger wavelength = 3e8 / 540,000 = 556 m

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(a)

Intensity = power / area

Intensity = P / $\pi$ r²

Intensity = 385 / $\pi$ * 0 .13²

Intensity = 7251 W/m²

(b)

E_max = sqrt ( 2I / c$\epsilon$_o)

E_max = sqrt ( 7251 * 2 / 3e8 * 8.85e-12)

E_max = 2337.2 V/m

(c)

B_max = E_max / c

B_max = 7.8e-6 T