A piece of pencil lead is connected in series with an ammeter and a power supply. The power supply is turned on. After a few minutes, although the potential difference across the pencil lead does not change, the current in the circuit increases significantly. Explain why the current increases.

More electrons become free due to the potential which are charge carriers. More the charge carriers, more the current.

Current causes a heating effect. Resistance of lead decreases/ n increases [I=nAve]. Current increase

Explanation:

we need to know the time interval during which the force acts. impulse of force = momentum change

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.