A source of sound moves toward a stationary observer. Compared to when the source was at rest, the observer perceives:
AHigher frequency and lower wavelength
BLower frequency and higher wavelength
CSame frequency but higher amplitude
DFrequency depending on the material
Explanation
📌 Doppler effect: source moving toward observer compresses the wavefronts. Observer perceives higher frequency (higher pitch) and correspondingly shorter wavelength. Distractor B: describes receding source; C: amplitude, not shifted; D: sound speed depends on material, but frequency shift is due to relative motion.