To produce work a gas is expanded adiabatically from 3 MPa and 300oC to 80 kPa in a piston-cylinder device. Which of these two choices –air with an isentropic expansion efficiency of 90% or neon with an isentropic expansion efficiency of 80% – will produce the most work?

Explanation:

Check attachment for solution

Given that, .

The initial gas pressure is

P1 = 3 MPa

The initial gas temperature

T1 = 300°C

The final gas pressure is

P2 = 80 KPa

Which are of two choices

1. Air with an isentropic expansion of 90% efficiency

2. Neon with an isentropic expansion of 80% efficiency

We want to know which will produce more work

answer: d. a cme increases the amount of energy in the solar wind

explanation:

coronal mass ejections, also called cmes, are large clouds of plasma and magnetic field that erupt from the sun. only when the cloud is aimed at earth will the cme hit earth and therefore cause impacts. high-speed solar wind streams come from areas on the sun known as coronal holes.