All categories

3 years ago

A heat engine has a cold reservoir of 250°C and a hot reservoir of 715°C. What is the efficiency of the engine?

2 answers:

6 0

If the heat engine is a perfect carnot cycle engine, then
efficiency = (T2-T1)/T2
where T1=temperature of cold reservoir ( ° K) = 250+273.15 = 523.15
T2=temperature of hot reservoir ( ° K) = 715+273.15 = 988.15

Therefore
efficiency = (T2-T1)/T2 = (988.15-523.15)/988.15 = 0.4706 = 47%

Note: this is the theoretical maximum efficiency of a perfect heat engine. Real-life engines do not achieve this value.

Illusion [34]3 years ago

5 0

The answer is A. 65.0% for plato users, i got 100% on the test :)

You might be interested in

If the resultant of two velocity vectors of equal magnitude is also of the same magnitude, then which statement must be correct?

Tamiku [17]

The correct option is C) The angle between the vectors is 120°.

Why?

We can solve the problem and find the correct option using the Law of Cosine.

Let A and B, the given two sides and R the resultant (sum),

Then,

$R=A=B$

So, using the law of cosines, we have:

$R^{2}=A^{2}+B^{2}+2ABCos(\alpha)\\ \\A^{2}=A^{2}+A^{2}+2*A*A*Cos(\alpha)\\\\0=A^{2}+2*A^{2}*Cos(\alpha)\\\\Cos(\alpha)=-\frac{A^{2}}{2*A^{2}}=-\frac{1}{2}\\\\\alpha =Cos(-\frac{1}{2})^{-1}=120\°$

Hence, we have that the angle between the vectors is 120°. The correct option is C) The angle between the vectors is 120°

Have a nice day!

4 0

3 years ago

If the potential difference across the bulb in a camping lantern is 9.0 V, what is the

Gre4nikov [31]

Answer:

Explanation:

The potential difference across the terminal as the same and thats because we are assuming that the source has no internal resistance.

Internal resistance are usually little resistances in the supply.

4 0

3 years ago

Convert 56 kilometers to inches

svlad2 [7]

The conversion for km to inches is:

1km=39370.1in

Now we can solve for 56 km..

56km=39370.1*56
56km=<span> 2204725.6in

Answer=2,204,725.6in</span>

7 0

3 years ago

What is the equivalent resistance of a circuit that contains two 50.00

Whitepunk [10]

Answer:

Explanation:

Resistors in series add. There is only one path the current can take. That's why Christmas Tree lights sometimes give a lot of trouble. If a bulb burns out, it could be any one of them and time is needed to find the burned out bulb.

That being the case R = R1 + R2

R1 = 50 ohms

R2 = 50 ohms

R = 50 + 50

R = 100 ohms

Answer A

4 0

3 years ago

Read 2 more answers

What is weight?

Over [174]

Answer:

Explanation:

plzzzzzzz Mark my answer in brainlist and follow me

4 0

3 years ago

Read 2 more answers