Ionising electromagnetic radiation | Exit Quiz | Oak National Academy

Electromagnetic (EM) radiation can transfer energy to objects. Match each of the following types of EM radiation with an effect that can occur when it transfers energy.

• gamma

• sunburn

• light

• generation of electricity by a solar panel

• microwaves

• heating of the water inside food

• infrared

• destruction of cancer cells

• ultraviolet

• heating of an object’s surface

Answer explanation

Ultraviolet can cause sunburn, gamma can kill cancer cells, infrared can heat the surface of an object, microwaves can heat the water inside food and light can cause a solar panel to produce electricity.

Some types of electromagnetic radiation can make an atom gain or lose one or more electrons and become charged. A charged atom is called an ...

(a)  

Answer explanation

An atom which is charged, because it has gained or lost at least one electron, is called an ion. The process of adding or removing an electron is called ionisation.

Which of the following is the most strongly ionising type of electromagnetic radiation?

• gamma rays

• infrared waves

• microwaves

• ultraviolet waves

• X–rays

Answer explanation

Gamma rays, X–rays and ultraviolet waves can all cause ionisation. Gamma rays have the highest frequency and are the most strongly ionising.

Which of the following increases the potential harm when electromagnetic radiation hits a living organism?

• increasing the intensity of the radiation

• increasing the frequency of the radiation

• increasing the wavelength of the radiation

• increasing how long exposure to the radiation lasts

Answer explanation

At higher frequencies, each ‘packet’ of radiation transfers more energy. At higher intensities, there are more packets per second. In a longer time interval, more packets hit the organism. So any of these three increases the potential harm.

Which of the following can happen when an atom absorbs radiation?

• An electron becomes ‘excited’.

• An electron is ejected from the atom.

• An electron moves to a lower energy level.

• An electron moves to a higher energy.

Answer explanation

If the radiation transfers enough energy, the electron may be ejected from the atom. This is called ionisation. If less energy is transferred, the electron may stay within the atom but move to a higher energy level. The electron is now ‘excited’.

Match each of the following types of electromagnetic radiation to one of its uses.

• gamma rays

• detecting fake bank notes

• X–rays

• sterilising medical equipment

• ultraviolet

• scanning bags at security checks

Answer explanation

Hidden markings on real bank notes become visible when ultraviolet light is shone on them. X–rays can be used to see inside bags in airport security checks. Gamma rays can be used to destroy microbes on medical equipment.