Physics 5054 · O Level · Electromagnetic spectrum

Electromagnetic spectrum — practice question

A star gives off electromagnetic radiation over a spread of wavelengths. Fig. 4.1 shows how the brightness of the star’s radiation changes with wavelength. The radiation from the star is brightest at one wavelength.
(a)[1]

Determine the wavelength at which the radiation reaches its maximum brightness.

(b)[1]

The visible part of the electromagnetic spectrum lies between $4.0 \times 10^{-7}\,\text{m}$ and $7.0 \times 10^{-7}\,\text{m}$. The radiation in (a) is just beyond the visible section of the electromagnetic spectrum. State the name of the spectral region that contains the radiation in (a).

(c)[3]

Determine the frequency of the radiation in (a). The speed of light is $3.0 \times 10^8\,\text{m s}^{-1}$.

Worked solution & mark scheme

This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: 1.15–1.25 × 10⁻⁶ m

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