Answer: The symbol representing the result of a gas expanding against a constant pressure is W
Explanation:
According to first law of thermodynamics, energy can neither be destroyed nor created but rather transferred to one place to another and converted to and from other energy forms.
The mathematical form of first law of thermodynamics is:

where
= change in internal energy
q = heat absorbed or released
W = work 
P = pressure
= volume change
Thus the changes in heat or work leads to change in internal energy.
Answer is B -273 degrees C
Answer:
a) 20 m/s
b) 37.5 m)s
Explanation:
Average speed = total distance ÷ total time
=> (a) average speed of a car that travels 400m in 20s
= 400/20 = 20 m/s
& (b) average speed of an athlete who runs 1500m in 4 minutes (or 4×60=240 seconds)
= 1500/240 = 37.5 m/s
The process that powers stars is C)fusion
Answer:
(i) false
(ii) true
(iii) true
(iv) false
Explanation:
(i) The ratio of Cp and Cv is not constant for all the gases. It is because the value of cp and Cv is different for monoatomic, diatomic and polyatomic gases.
So, this is false.
(ii) For monoatomic gas
Cp = 5R/2, Cv = 3R/2
So, thier ratio
Cp / Cv = 5 / 3 = 1.67
This statement is true.
(iii) for diatomic gases
Cp = 7R/2, Cv = 5R/2
Cp / Cv = 7 / 5 = 1.4
This statement is true.
(iv) It is false.