The frequency of bird chirping hear by hiran will be 1.77 kHz.
<u>Explanation:</u>
As per Doppler effect, the observer will feel a decrease in the frequency of the receiving signal if the source is moving away from the observer. So the shifted frequency is obtained using the below equation:

Here , c is the speed of sound, Vs is the velocity of source with which it is moving away. f is the original frequency of source and f' is the frequency shift heard by the observer.
As here, f = 1800 Hz, Vs= 6 m/s and c = 343 m/s, then

So, the frequency of bird chirping hear by hiran will be 1.77 kHz.
Answer:
The work done on the gas is equal to the area under the curve pv diagram w = area of triangle = 1/2 (base)(height) = 1/2 (BC)(Ac) = 1/2 (3v - v)(3p - p) = 1/2 (9 vp - 3 vp - 3vp + vp) = 4 vp/2 W = 2 vp
Check attachment for the diagrammatic representation
Choice 'b' is one possible way to state
Newton's second law of motion.
The other choices are meaningless.
Given:
500 containers ; 5 of these are defective.
A = event that 1st is defective = 5/500
B = event that 2nd is defective = 4/499
C = event that 3rd is defective = 3/498
a) 4/499
b) 5/500 * 4/499 = 20/249,500 = 1/12,475
c) 495/500 * 494/500 = 244,530 / 250,000 = 24,453/25,000
d) 5/500 * 4/499 * 3/498 = 60/124,251,000 = 1/2,070,850