When an ambulance with a blaring siren moves towards an observer, the pitch of the siren appears to be higher. This is due to: MCQ with Answer and Explanation
When an ambulance with a blaring siren moves towards an observer, the pitch of the siren appears to be higher. This is due to:
A. Interference of sound waves
B. The Doppler Effect
C. Acoustic resonance
D. Reverberation
Answer: Option B
Solution (By JKSSB Mock Tests)
The Doppler Effect is the apparent change in the frequency (and thus pitch) of a wave due to the relative motion between the source and the observer. As the ambulance approaches, sound waves get compressed, increasing the perceived frequency (higher pitch). As it moves away, waves stretch, lowering the frequency.
Explanation:
Higher pressure raises boiling point, so water can reach temperatures above 100°C, cooking food faster. At high altitudes, pressure cooker compensates for lower atmospheric pressure.
Explanation:
Lenz's law is a consequence of the conservation of energy. It dictates that an induced electromotive force (EMF) always gives rise to a current whose magnetic field opposes the change in original magnetic flux that produced it. If a north pole approaches a coil, the coil face becomes a north pole to repel the magnet, requiring work to overcome.
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