A heat engine operating between the
temperatures T1 and T2 takes in Qı calories at
temperature T1 and gives up Q2 calories at
temperature T2. The efficiency of this heat
engine is
(Q1 - Q2)/Q2.
(Q1 - Q2)/Q1.
(T2 - T1/T2.
Q2/(Q1 - Q2).
O T1/(T1-T2).

Answer:

(Q1 - Q2)/Q1

Explanation:

The efficiency of any device can be given by the following formula:

[tex]Efficiency = \eta[/tex] = Output/Input

Now, for engine the output is the mechanical work that it does and the input is the heat that it absorbs. Let:

W = Work Done by the engine

Q₁ = Heat Absorbed by the System

Q₂ = Heat Rejected by the System (Because According to 2nd Law of Thermodynamics, engine can not convert the entire heat into work without rejection of some heat)

Therefore, the equation becomes:

[tex]\eta = \frac{W}{Q_{1}}[/tex]

but, the work can be written as the difference between the absorbed heat and the rejected heat. Hence,

[tex]\eta = \frac{Q_{1} - Q_{2}}{Q_{1}}[/tex]

Therefore, the correct option is:

(Q1 - Q2)/Q1

Dominic has a brain injury. Why is this MOST likely to be a serious injury?

Which of the following is an example of a double replacement reaction?

A. 3Fe + 2O2 → Fe3O4
B. BaCl2 + K2CO3 → BaCO3 + 2KCl
C. NiCO3 → NiO + CO2
D. Cl2 + 2NaBr → 2NaCl + Br2

Four different objects are placed on a number line at 0. The chart describes the motion of each object.
Object
Motion
W
3 units left, then 3 units right
Х
6 units right, then 18 units right
Y
8 units left, then 24 units right
Z
16 units right, then 8 units left
Using the information in the chart, the distance and displacement of each object can be determined. Which object has
a distance that is three times as great as its displacement?
W
Х
Z