Answer:
Option B, Fix the piston in place so the volume of the pas remains constant
Explanation:
As we know

The effect on variable due to another variable can be studied by keeping the third variable constant.
Hence, in order the study the variation of temperature with pressure or vice versa, the volume needs to fixed at a certain value.
Hence, option B is correct
Answer:
3.24×10⁸ J, or 324 MJ
Explanation:
"kWh" is a kilowatt-hour. It's the energy used by 1 kilowatt of power after one hour.
A kilowatt is a kilojoule per second.
90 kWh
= 90 kW × 1 hr
= 90 kJ/s × 1 hr
= 90 kJ/s × 3600 s
= 324,000 kJ
= 324,000,000 J
The energy is 3.24×10⁸ J, or 324 megajoules.
I think 6.1m i’m not sure sorry if i’m wrong