Electromagnetic Wave Production + Interactions + Hazards

How can radio waves be produced?

By oscillations in electrical circuits.

What happens when radio waves are absorbed by a suitable electrical circuit?

They can produce an alternating current at the same frequency as the radio wave.

How are electromagnetic waves produced by atoms?

Changes in atoms or their electrons can result in electromagnetic radiation being emitted.

Where do gamma rays originate?

From changes in the nuclei of atoms.

What happens when electromagnetic waves are absorbed by a material?

They transfer energy to the material.

Why do different materials interact differently with electromagnetic waves?

Absorption, transmission, reflection and refraction depend on the material and wavelength.

What is ionising radiation?

Radiation with enough energy to remove electrons from atoms, forming ions.

Which electromagnetic waves are strongly ionising?

X-rays and gamma rays.

Why can X-rays and gamma rays be harmful?

They can ionise atoms in living cells, damaging DNA and increasing the risk of cancer.

What are the hazards of excessive ultraviolet exposure?

Premature skin ageing and increased risk of skin cancer.

Why can ultraviolet radiation damage skin?

It can cause chemical changes and damage to DNA in skin cells.

Why are X-rays useful but potentially dangerous?

They can penetrate soft tissue for imaging, but their ionising effects can damage cells.

What affects the risk from exposure to harmful electromagnetic radiation?

The type of radiation and the size of the dose.

What is radiation dose?

A measure of the risk of harm from exposure to radiation.

Why should unnecessary exposure to ionising radiation be avoided?

To reduce the risk of cell damage and cancer.

Can infrared radiation transfer thermal energy?

Yes, infrared radiation can be absorbed and increase an object's thermal energy.

Why can microwaves heat food?

They transfer energy to water and other molecules in the food, increasing its temperature.

Why are X-rays more penetrating than visible light in many materials?

They have different interactions with matter, allowing them to pass through some materials that absorb visible light.

Why is gamma radiation used in some cancer treatments?

It can damage or destroy cancer cells.

Why must radiation exposure be controlled in medical treatments?

To minimise damage to healthy tissue.