Question

Based on its surface temperature of 6,000 K, most photons that leave the Sun's surface lie in which region of the electromagnetic spectrum?
A) Microwave
B) Infrared
C) Visible
D) Ultraviolet
E) X-ray

Answer 1

Answer:

C) Visible

Explanation:

The electromagnetic (EM) spectrum is the range of all types of electromagnetic radiation. The types of electromagnetic radiation that make up the electromagnetic spectrum are radio waves, microwaves, infrared light, visible, ultraviolet light, X-rays and gamma-rays.

Region             Wavelength

Radio                >0.1 cm

Infrared              7000 Â to 0.1 cm

Visible               4000 to 7000 Â

Ultraviolet         100 to 4000 Â

X-ray                  0.1 to 100 Â

Gamma ray        <0.1 Â

Most electromagnetic radiation from space is unable to reach the surface of the Earth. Earth's atmosphere is opaque to most wavelengths expect those in the visible part of the spectrum and in some parts of the radio.

From Wein's Law, the black-body radiation curve for different temperatures will peak at different wavelengths that are inversely proportional to the temperature.

                      λ$_{max} = \frac{b}{T}$

Where,

λ$_{max}$ is the maximum wavelength

b is Wien's displacement constant = 2.9 × 10⁻³ Km = 0.290 Kcm

T is the absolute temperature in kelvins

                     λ$_{max} = \frac{0.290 Kcm}{6000}$

                     λ$_{max}$ = 4.83 × 10⁻⁵ cm

                    λ$_{max}$ = 4830 Â

This wavelength 4830 Â lies in the visible region of the Electromagnetic spectrum.