Q1 · easy · AI-verified
Radar works on the principle of which of the following?
- Refraction of radio waves
- Reflection of sound waves
- Absorption of radio waves
- Reflection of radio waves
Q2 · medium · AI-verified
BrahMos is a cruise missile jointly developed by India and which country?
- Russia
- France
- USA
- Israel
Q3 · hard · AI-verified
SONAR uses which type of waves to detect underwater submarines, unlike RADAR which uses electromagnetic waves?
- Infrared waves
- Ultrasonic (sound) waves
- Microwave radiation
- X-ray waves
Q4 · hard · AI-verified
A sonar system emits an ultrasonic pulse that returns after 3 seconds. If the speed of sound in seawater is 1500 m/s, what is the depth of the submarine detected?
- 1500 m
- 2250 m
- 750 m
- 4500 m
Q5 · hard · AI-verified
A radar pulse is transmitted and its echo is received after 400 microseconds. If the speed of electromagnetic waves is 3 × 10⁸ m/s, what is the distance of the target from the radar?
- 45 km
- 30 km
- 120 km
- 60 km