I think the answer for the question above its b 1.2
Answer: 60.56
Explanation: Just multiply 3.785 by 16.
Answer:
intensity of sound at level of microphone is 0.00139 W / m 2
sound intensity level at position of micro phone is 91.456 dB
EXPLANATION:
Given data:
power of sound P = 31 W
distance betwen microphone & speaker is 42 m
a) intensity of sound at microphone is calculated as


= 0.00139 W / m 2
b) sound intensity level at position of micro phone is

where I_o id reference sound intensity and taken as

= 91.456 dB
Answer:
At some point on say, the receiving screen, light emanating from the left side of the slit will be out of phase (a difference of 1/2 wavelengths) from light coming from the center of the slit.
Thus for every point that is left of the center of the slit, there will be a point on the right side of the slit that is out of phase,
There will be no light on the screen at that particular point and thus there will be a dark fringe there.
That is the basic explanation for the appearance of dark and bright fringes on the receiving screen.
<h2>The option ( c ) is correct</h2>
Explanation:
When we apply the force on any body , the inertia comes into play . It is the tenancy of the the body to oppose the force which tends to change its state .
In first case the train tries to change its state from rest to motion . Thus the inertia of rest opposes this tendency.
In the second case , the train tries to come from motion to the state of rest . Thus again , inertia opposes it .
Therefore inertia is the factor which creates difficulty in both case . Hence option ( c ) is correct