Skip to content
Login Register

#thermal radiation

3 public questions tagged with this topic.

Applications of EM Waves in Communication and Medicine

Which type of electromagnetic waves are emitted by hot bodies and molecules?

**Radio waves** effective for long-distance communication because low frequency waves diffract around Earth curvature and reflect from ionosphere, enabling beyond line-of-sight, used in AM (≈10⁶ Hz) ground wave, short wave sky wave. Microwaves used for satellite due to high frequency penetrates ionosphere and directional beam. The document states that infrared waves are produced by hot bodies and molecules, often referred to as heat waves. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Infrared waves, illustrating EM wave transverse nature and

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

View Details
Applications of EM Waves in Communication and Medicine

Which type of electromagnetic waves are produced by the vibration of atoms and molecules?

**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 infrared waves are produced by the vibration of atoms and molecules. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Infrared waves, 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

View Details
Infrared, Visible Light and Applications

Why are infrared waves sometimes referred to as heat waves?

**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. The document explains that infrared waves are absorbed by water molecules, increasing their thermal motion and thus heating the material. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields They increase thermal motion in materials, illustrating EM wa

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

View Details