Microwaves

3 marks · Easy

Explain why it is important that microwave ovens have metal screens or mesh on their doors. What could happen if there was no screen?

Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.

Show answer

Also accept: Metal screens reflect/stop microwaves escaping; microwaves could heat body tissue if they escape; without screen, user could be harmed

Common mistakes: Vague answers such as 'for safety' without explanation

Show mark scheme and worked solution

Marking points

M1 · 1 mark · States that screens reflect or block microwaves from leaving the oven.

M2 · 1 mark · Microwaves escaping can heat human body tissue if unprotected.

M3 · 1 mark · States the importance is to protect users from potential harm (e.g., skin burns or injury).

Worked solution

The metal screen or mesh is needed because it reflects or absorbs microwaves, stopping them from escaping the oven. If there were no screen, microwaves could leak out, potentially heating and damaging the body tissues of anyone nearby. This makes the screens necessary for user safety.