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#radio spectrum

2 public questions tagged with this topic.

Electromagnetic Spectrum - Radio Waves and Microwaves

What is the frequency range of the FM radio band?

**Microwaves** λ≈10⁻³ to 0.3 m, f≈10⁹ to 10¹² Hz, produced by klystron/magnetron, used in microwave ovens because frequency ≈2.45 GHz matches rotational resonance of water molecules, causing dielectric heating, also radar, satellite communication due to small wavelength allows directional beams. The document states that the FM radio band extends from 88 MHz to 108 MHz . Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields 88 MHz to 108 MHz, illustrating EM wave transverse nature and Maxwell's displacement current concept.

Ref: NCERT > Physics Book > Electromagnetic Waves > Electromagnetic Spectrum - Radio Waves and Microwaves

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Electromagnetic Spectrum - Radio Waves and Microwaves

Which frequency range corresponds to the ultrahigh frequency (UHF) band used by cellular phones?

**Hertz experiment** produced radio waves using spark gap LC oscillator, detected with loop antenna, confirming Maxwell's prediction, frequency ≈10⁸ Hz, wavelength ≈3 m, demonstrating EM waves travel at c, transverse, can be reflected, refracted, polarized. The document mentions that cellular phones use radio waves in the UHF band, which typically falls within the general radio wave range of 500 kHz to 1000 MHz , but UHF specifically is higher, often around 300 MHz to 3 GHz . Here, we approximate within radio range. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f

Ref: NCERT > Physics Book > Electromagnetic Waves > Electromagnetic Spectrum - Radio Waves and Microwaves

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