Which of the following device works on the principle of reflection of sound:
a) Stethoscope
b) SONAR
c) Electric Bell
1
Both a and b
2
Both b and c
3
Both a and c
4
All a, b and c are correct
Which of the following device works on the principle of reflection of sound:
a) Stethoscope
b) SONAR
c) Electric Bell