Q: Which one of the following principles of physics is primarily used in sonography, a medical diagnostic process?
(a)Resonance
(b)Superposition of waves
(c)Doppler effect
(d)Standing wave
Correct Answer: (c)
The correct answer is (c): डॉपpler प्रभाव (Doppler effect). Subject: Science & Technology | Sub-topic: Physics Note: This answer was determined through AI-based research. Verify against the official answer key when available.