A closed system contains 30g of gas. How much heat(in joules) is added to or rejected by the system to produce 5000 N-m of work
1 answer:
Answer : The heat rejected by the system is 1000 J
Explanation :
As per first law of thermodynamic,
where,
= internal energy of the system
q = heat added or rejected by the system
w = work done of the system
First we have to determine the internal energy for 30 grams of gas.
As, 1 gram of gas has internal energy = 200 J
So, 30 grams of gas has internal energy = 200 × 30 = 6000 J
Now we have to determine the heat of the system.
= -6000 J
w = 5000 N.m = 5000 J
Now put all the given values in the above formula, we get:
The negative sign indicate that the heat rejected by the system.
Hence, the heat rejected by the system is 1000 J
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Answer:
Explanation:
Plate separation, d = 1.76 cm = 0.0176 m
Area of plates, A = 25 cm^2 = 0.0025 m^2
V = 255 V
(a) Capacitance of capacitor
C = 1.258 x 10^-12 F
charge is same before and after immersion as the battery is disconnected
q = C V
q = 1.258 x 10^-12 x 255 = 3.2 x 10^-10 C
(b)
Capacitance before, C = 1.258 x 10^-12 C
capacitance after, C' = k x C = 80 x 1.258 x 10^-12 = 100.64 x 10^-12 C
Where, k is the dielectric constant of water = 80
Potential difference after immersion, V' = V / k = 255 / 80 = 3.1875 V
(c) initial energy,
Final energy