Question

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.

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Answer 1

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

Step-by-step explanation: