Electromagnetic Spectrum

Question 1

The EM spectrum definition

Answer 1

The range of wavelengths or frequencies over which electromagnetic radiation extends.

Question 2

The dual nature of EM radiation / Wave-particle duality

Answer 2

Some aspects of EM radiation can best be explained using a wave model and some aspects can best be explained using a particle model.

Question 3

4 Main Electromagnetic Interactions:

Answer 3

• The force of attraction or repulsion between electric charges is inversely proportional to the square of the distance between them.
• Magnetic poles come in pairs that attract and repel each other, much as electric charges do.
• An electric current in a wire produces a magnetic field whose direction depends on the direction of the current.
• A moving electric field produces a magnetic field, and vice versa.

Question 4

Speed of light

Answer 4

3 x 10^8 m.s-1

Question 5

Photon

Answer 5

The smallest discrete amount (or Quantum) of electromagnetic radiation.

Question 6

EM radiation explination

Answer 6

EM radiation is created when an atomic particle, such as an electron, is accelerated by an electric field, causing it to move.
The movement produces oscillating electric and magnetic fields, which travel at right angles to each other in a bundle of light energy called a photon.
Photons travel in harmonic waves at the fastest speed possible in the universe: 3 x 108 m.s-1 in a vacuum, also known as the speed of light.
This constant speed of light is represented by c.
BECAUSE EM RADIATION IS PROPAGATED BY THE INTERACTION OF CONSTANTLY CHANGING ELECTRIC AND MAGNETIC FIELDS THAT DO NOT NEED A MEDIUM, EM RADIATION DOES NOT REQUIRE A MEDIUM

Question 7

What kind of waves are EM waves?

Answer 7

Transverse waves
EM waves are produced by accelerating charged particles, resulting in occulting electric and magnetic fields. These fields oscillate at right angles to the direction of the propagation of the wave and each other

Question 8

EM wave equation

Answer 8

c = f x λ
c = speed of light = 3 x 10^8

Question 9

EM as a wave

Answer 9

• Wide range of frequencies and wavelengths.
• All move at the speed of light.
• No medium needed.

Question 10

EM as a particle

Answer 10

• Packets of energy called photons.

- Energy of photon is related to the wavelength of electromagnetic radiation according to Plank’s constant.

Question 11

Energy of a photon formula

Answer 11

E = hf
OR
E = f x c / λ
E - Energy in Joules
c- speed of light
h - planck's constant (6.63 x 10^-34 J.s)

Question 12

Radio waves uses

Answer 12

communications including voice, data and entertainment media.

Question 13

Microwaves uses

Answer 13

high-bandwidth communications, radar and as a heat source for microwave ovens and industrial applications.

Question 14

Infrared waves uses

Answer 14

invisible to human eyes, but we can feel it as heat if the intensity is sufficient.

Question 15

Ultraviolet uses

Answer 15

UV light is a component of sunlight; however, it is invisible to the human eye. It has numerous medical and industrial applications, but it can damage living tissue.

Question 16

X- rays uses

Answer 16

medical

Question 17

Gamma ray uses

Answer 17

Gamma radiation causes damage to living tissue, which makes it useful for killing cancer cells when applied in carefully measured doses to small regions.
Uncontrolled exposure, though, is extremely dangerous to humans.

Question 18

EM Spectrum layout:

Answer 18

Gamma ray | X-ray | Ultraviolet | Visible Light | Infrared | Microwave | Radio

Gamma ray: Shorter wavelength, higher energy, higher frequency

Radio waves: Longer wavelength, lower energy, lower frequency.