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#frequency range

9 public questions tagged with this topic.

Applications of EM Waves in Communication and Medicine

Which frequency range includes TV waves according to the document?

**X-rays and gamma rays in medicine** X-rays imaging because bone absorbs more than tissue, contrast, CT scan uses multiple X-ray projections, gamma knife uses focused gamma rays to destroy tumor with minimal surrounding damage, illustrating high-energy EM wave medical use. The document states that TV waves range from 54 MHz to 890 MHz . Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields 54 MHz to 890 MHz, illustrating EM wave transverse nature and Maxwell's displacement current concept.

Ref: NCERT > Physics Book > Electromagnetic Waves > Applications of EM Waves in Communication and Medicine

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Applications of EM Waves in Communication and Medicine

Which frequency range corresponds to short wave bands used in radio communication?

**Microwaves in ovens** cause water molecules to rotate at 2.45 GHz, friction heats food, penetration depth few cm, efficient heating, also radar uses reflection of microwaves from objects, Doppler shift measures speed, medical diathermy uses microwaves for tissue heating. The document states that frequencies up to 54 MHz are used for short wave bands in radio communication. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Up to 54 MHz, illustrating EM wave transverse nature and Maxwell's displacement current concept.

Ref: NCERT > Physics Book > Electromagnetic Waves > Applications of EM Waves in Communication and Medicine

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Energy, Intensity and Momentum of EM Waves

Which frequency range corresponds to the FM radio band as per the document?

**Poynting vector** S = E×B/μ₀ gives energy flow (W/m²), magnitude S = E B/μ₀, average = E₀ B₀/(2μ₀) = intensity, direction of propagation, showing energy transport perpendicular to E and B. 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 > Energy, Intensity and Momentum of EM Waves

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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 AM radio band as per the document?

**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 AM radio band ranges from 530 kHz to 1710 kHz . Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields 530 kHz to 1710 kHz, 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

What is the approximate frequency range of microwaves used in radar systems?

**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 states that microwaves are in the gigahertz (GHz) range, typically used for radar systems. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Gigahertz (GHz) range, 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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Infrared, Visible Light and Applications

What is the frequency range of visible light?

**Infrared waves** λ≈700 nm to 1 mm, f≈10¹² to 4×10¹⁴ Hz, produced by hot bodies and molecular vibrations, wavelength range as per document 700 nm-1 mm, used in remote sensing because IR penetrates haze, thermal imaging detects IR emitted by objects, remote controls, effective for sensing temperature. Visible light ranges from about 4 × 10¹⁴ Hz to 7 × 10¹⁴ Hz , as stated in the document. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields 4 × 10¹⁴ Hz to 7 × 10¹⁴ Hz, illustrating EM wave transverse nature and Maxwell's displacement current concept.

Ref: NCERT > Physics Book > Electromagnetic Waves > Infrared, Visible Light and Applications

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Electromagnetic Spectrum - Radio Waves and Microwaves

Which frequency range corresponds to short wave bands used for radio communication?

**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 states that frequencies up to 54 MHz are used for short wave bands in radio communication. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Up to 54 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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