Answer:
option (c)
Explanation:
According to the doppler's effect, the frequency of sound decreases.
If there is a relative motion between the source and the observer, the frequency of sound changes apparently.
the formula of the doppler effect is given by
where, f is the real frequency, v be the speed of sound, vo be the speed of the observer, here, the bus is the observer.
So, the value of f' < f
Answer:
The work done on the gas = 2PV
Explanation:
In this question, we need to apply the basic gas laws to determine the word done.
For this question, we need to draw a PV diagram (a pressure-volume diagram), which I have made and attached in the attachment. So please refer to that attachment. I will be using this diagram to solve for the work done on the gas.
So, Please refer to the attachment number 1. where x -axis is of volume and y-axis is of pressure.
As we know that, the work done on the gas is equal to the area under the curve.
W = Area of the triangle
W = 0.5 x ( base) x ( height)
W = 0.5 x (BC) x (AC)
W = 0.5 x (3V-V) x (3P-P)
W = 2PV
Hence, the work done on the gas = 2PV
