03 – Oscillations and Waves

2020-mcq-3

The threshold of hearing of a normal human ear is 10-12 Wm-2. This corresponds to a sound intensity level of
(1) 0 dB (2) 1 dB (3) 10 dB (4) 12 dB (5) 120 dB

lets we see it.

Then answer is (1). It is unnecessary to try equations. We already know it is equal to zero if the threshold of hearing of a normal human ear is 10-12 Wm-2.

2020-mcq-7

Which of the following statements made regarding seismic waves is incorrect?
(1) All seismic waves are mechanical waves and require are medium to propagate.
(2) Primary (P) waves are longitudinal and secondary (s) waves are transverse.
(3) Speed of S – waves is less than of P – waves.
(4) S – waves can travel through both liquid and solid media.
(5) P – waves can travel through both liquid and solid media.