MyQuestionIcon

1

You visited us 1 times! Enjoying our articles? Unlock Full Access!

2nd Law of Thermodynamics

An engineer c...

Question

An engineer claims to have made an engine delivering 10 kW power with fuel consumption of 1gm/sec. The calorific value of fuel is 2 kcal/gm.This claim is

A

valid

No worries! We‘ve got your back. Try BYJU‘S free classes today!

B

invalid

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

C

depedent on engine design

No worries! We‘ve got your back. Try BYJU‘S free classes today!

D

depedent on load

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is C invalid
Efficiency of a Carnot engine is
$η = \frac{W}{Q_{h}} = 1 - \frac{T_{c}}{T_{h}}$
$W = Q_{h} (1 - \frac{T_{c}}{T_{h}}) = (1) (2) (1 - \frac{T_{c}}{T_{h}}) k c a l / s e c$
$10 k W = 2 (4.2) (1 - \frac{T_{c}}{T_{h}}) k J / s$
$\frac{10}{8.4} = 1 - \frac{T_{c}}{T_{h}}$
$\frac{T_{c}}{T_{h}} = 1 - 1.19 = - 0.19$
Ratio of absolute temperatures can be not be negative. So, the claim by the engineer is invalid.

Suggest Corrections

thumbs-up

0

Similar questions

Q. A Brayton gas power cycle is used to power a jet engine. The fuel used has calorific value of 50 Mj/kg. Jet engine has..a velocity of 800 m/s and produces net thrust of 6 kM If the fuel consumption is 0.2 kg per hour per N of thrust. The overall efficiency of gas power cycle is _____ % ( Correct upto 2 decimal places)

Q. An inventor claims to have developed an engine that takes in

1000 J

of heat and produces

1500 J

of work during each cycle. Comment on the validity of this claim.

Q. The specific fuel consumption per BHP hour for diesel engine is approximately

Q. A four-cylinder, four stroke petrol engine is to develop 40 kW at 40 rev/s, when it is designed for a volumetric compression ratio of 10.0 to 1. The ambient air- conditions are 1 bar and

18^{\circ} C

, and the calorific value of the fuel is 44 MJ/kg. If the indicated overall efficiency is 50% of the corresponding air-standard Otto cycle, and the mechanical efficiency is 90%, then the specific fuel consumption ____ g/MJ of brake work. The specific heat capacity ratio for air is 1.4. (Correct upto one decimal place).

Q. An engine manufacturer claims to have a engine capable of developing 30 hp by receiving heat input of 600 kcal per minute and it works between temperature of

227^{\circ} C

27^{\circ} C

, then his claim is

View More

Join BYJU'S Learning Program

similar_icon

Related Videos

lock

Second Law of Thermodynamics

PHYSICS

Watch in App

explore_more_icon

Explore more

2nd Law of Thermodynamics

Standard XII Physics

Join BYJU'S Learning Program

CrossIcon