We have that a blackbody radiator either constantly absorbs energy or constantly emits energy, depending on its surroundings. In this case, the energy is continuously and smoothly decreasing, thus it cannot be like B and C.
The energy loss or gain is also monotonous, it has the same direction; a radiator cannot gain energy at some point and then lose some. Hence, it does not resemble a wave either. The most appropriate model is the ramp. Energy is constantly emitted to surroundings and it decreases monotonically.
Answer:
4.23 beats / seconds
Explanation:
Frequency heard = f = f₁ - f₂
f₂ = f₁ √ ( F₂ / F₁)
f = f₁ - f₁ √ ( F₂ / F₁) = f₁ ( 1 - √ ( F₂ / F₁) = 523 Hz ( 1 - 0.9919 ) = 4.23 beats / seconds
Well it would not be c as it wouldn't be a transmitter. Since it's a power plant it wouldn't be Transmitter, and heated water makes steam it has to be B Steam, Turbine.