Test: First Law of Thermodynamics - 1 - Mechanical Engineering MCQ

The First Law of Thermodynamics is basically based on the Law of Conservation of Energy.

There can be no machine which would continuously supply mechanical work without some other form of energy disappearing simultaneously. It is fictitious machine.

= 0.1 χ 10⁶ (0.15-0.3)
= -15Kj
-25Kj

Engine power,

Photosynthesis takes place by absorbing heat and energy from the surroundings. Since, endothermic reaction is a reaction in which the system absorbs heat from its surroundings, the reaction that takes place during photosynthesis is an endothermic reaction.

W=(10×100+50×100)5×60=Q=mCv​ΔT=2×717ΔT.∴ΔT=313∘C.

The paddle-wheel work done on the air can be calculated using the formula: W=P△V, where W is the work done, P is the constant pressure, and △V is the change in volume

Since the process is isochoric (constant volume) in an insulated container, the work done is equal to the heat added to the system. Therefore, W = Q

The heat added to the system can be calculated using the formula: Q=mc△T, where Q is the heat added, m is the mass of the air (5 kg), c is the specific heat capacity of air at constant volume, and △T is the change in temperature

The specific heat capacity of air at constant volume is approximately 0.717 kJ/kg°C

Substitute the given values into the formula: Q = 5×0.717×100 = 358.5kJ

Therefore, the paddle-wheel work done on the air is 358.5 kJ

from the first law of thermodynamics Q = U + W

here internal energy will be same for all the path,hence the required equation will be Q = W

now the path which have higher work done will also have higher heat .

so, W₁<W₂<W₃

also,Q₁<Q₂<Q₃