Question

Thermodynamics

Question 1 Problems 1-3 are based on the following description Electrical energy is applied to a system enclosed inside the piston-cylinder device shown below. The voltage is 10 volts and the current is 2 amps for 20 seconds. During this time there is a heat transfer from the system to the outside equal to 90), the system expands 0.2 mata constant pressure of 200 kPa. The amount of electrical energy in J applied to the System is closer to: 200 0.4 250 600 400 2000 4100

2) The expansion work in J is closer to:

a)20

b)30

c)300

d).2

e)2000

f)4000

g)400

h)200

3) the increase in energy of the system in J is closer to:

a)90

b)200

c)110

d)600

e)3200

f)400

g)60

h)33

Answer 1

Ans! Not in options Welectric Visit 10x2x20 40OT amount of electric energy system supplied to Q2: Expansion work, wb = Piav (200 kPa) (0.2 m3) 40. k3 Wb 40 x103 J Q3: O-AW DE= E2 - Els ( wb- Welectric) (-90) (-90). ( 40.000 - 400) -39, 690 I Change in energy Ans: Not in options. of system