Answer:
C
Explanation:
During an investigation you want to investigate different variables.
First, we need to convert the pressure in SI units. Keeping in mind that

:

The initial and final volume of the gas are (keeping in mind that

):


So, the work done on the gas by the surrounding is

And the final positive sign means that this work corresponds to an increase in internal energy of the gas.
Answer:
changing the magnetic field more rapidly
Explanation:
According to Faraday's law, whenever there is a change in the magnetic lines of force, it leads the production of induced emf. The magnitude of induced emf is proportional to to the rate of change of flux.
Hence if the magnetic field inside a loop of wire is changed rapidly, the magnitude of induced emf increases in accordance with Faraday's law of electromagnetic induction stated above when the magnetic field is changed more rapidly, hence the answer.