Electromagnetic Radiation

Question 1

What is electromagnetic radiation?

Answer 1

Can be described in terms of waves and characterised in terms of wavelength (λ) and/or frequency (f)

Question 2

What is the relationship between wavelength and frequency?

Answer 2

The longer the wavelength the lower the frequency and the shorter the wavelength the higher the frequency.
Frequency and wavelength are inversely proportional.

Question 3

How is wavelength and frequency linked and what does it stand for?

Answer 3

They are linked by a constant c, the speed of light in a vacuum.

Question 4

What is the value of the speed of light?

Answer 4

3.00x10ms^8

Question 5

How are the different types of radiation arranged?

Answer 5

Arranged in order of wavelength and is known as the electromagnetic spectrum.

Question 6

what does the shorter wavelengths have?

Answer 6

High energy and highest frquency.

Question 7

What does the longer wavelength have?

Answer 7

Low energy and lowest frequency.

Question 8

What is the order of the electromagnetic spectrum?

Answer 8

Gamma-xrays-ultraviolet-visible-infrared-microwaves-radio waves.

Question 9

What are wavelengths of visible light?

Answer 9

expressed in nanometres, nm, x10^-9

Question 10

what is a photon?

Answer 10

A particle of light that carries a quantised energy proportional to the frequency of radiation

Question 11

What can electromagnetic radiation be described as?

Answer 11

a wave (has a wavelength and frequency) and as a particle, and is said to have a dual nature.

Question 12

What happens when electromagnetic radiation is absorbed or emitted?

Answer 12

It behaves like a stream of particles known as photons.

Question 13

How are energy and frequency linked?

Answer 13

By Planck’s constant (h) with a value of 6.63x10^-34

Question 14

What is L?

Answer 14

Avogadro’s constant which is 6.02x10^23moll^-1

Question 15

What happens when energy is transferred in an atom?

Answer 15

Electrons may use this energy to move to a higher energy level. These electrons are said to be excited.

Question 16

What happens when the electrons lose energy and move back to a lower energy level.

Answer 16

Energy is lost in the form of photons.

Question 17

How is line on an emission spectrum represent?

Answer 17

A line in an emission spectrum is produced when electrons are promoted to a higher energy level, fall to a lower energy level and photons are emitted with energy corresponding to the gap. (sometimes in the visible regions.)

Question 18

Why are there a series of lines at discrete wavelengths in an emission spectrum?

Answer 18

There are a series of lengths a discrete wavelengths because there are a series of different electron transitions between different energy levels.