Robert Watson-Watt was the inventor of:

Correct answer: Radar. Robert Watson-Watt developed radar in the 1930s.

Background: RADAR stands for Radio Detection And Ranging. Robert Watson-Watt developed it in Britain in the 1930s to detect aircraft.

• Needle: He did not invent the needle.
• Tube light: He did not invent the tube light.
• None of these: “None of these” is incorrect because radar is correct.

Did you know? Radar helped Britain in the Battle of Britain in 1940.

Memory trick: Watson-Watt → RADAR.