Oxygen at 50 lbf/in.2, 200 F is in a piston/cylinder arrangement with a volume of 4 ft3. It is now compressed in a polytropic process with exponent, n = 1.2, to a final temperature of 400 F. Calculate the heat transfer for the process.

The value of heat transfer during the process Q = - 29.49 KJ

Explanation:

Given data

= 50 = 344.7 k pa

= 0.113

F = 366.4 K

= 477.6 K

Poly tropic index n = 1.2

gas constant for oxygen = 0.26

From ideal gas equation

= m R

Put all the values in above equation we get

⇒ 344.7 × 0.113 = m × 0.26 × 366.4

⇒ m = 0.408 kg

Heat transfer in poly tropic process is given by

Q =

Put all the values in above formula we get

⇒ Q =

⇒ Q = 2.5 × 0.408 × 0.26 × ( 366.4 - 477.6 )

⇒ Q = - 29.49 KJ

This is the value of heat transfer during the process & negative sign shows that  heat is lost during the process.

when a device is used in a circuit in which the voltage is 81 v, the current flowing through the device is 3 a. what is the resistance of the device?

a. 27 ω

b. 40.5 a

c. 243 ω

d. 243 a

the correct answer is a. 27

when heated, the valance electrons increased their speed and transferred the heat from electron to electron.   i just took the test.