Distinguishing emf from potential difference (p.d.) in energy transfers

Steps:

• Emf equals work done by cell per unit charge, converting chemical to electrical energy.
• P.d. equals energy dissipated per unit charge across resistor, converting electrical to thermal energy.
• With negligible internal resistance and p.d. = emf = 6.0 V, all electrical energy from cell transfers to thermal in resistor.
• Evaluate options against these definitions to identify the matching statement.

Why C is correct:

• C accurately states emf as energy per unit charge from chemical to electrical in cell, and p.d. from electrical to thermal in resistor, aligning with standard definitions.

Why the others are wrong:

• A incorrectly attributes chemical-to-thermal transfer directly to p.d., bypassing electrical energy.
• B wrongly claims emf involves thermal energy in cell, not electrical.
• D is grammatically incomplete and redundantly mentions "the cell" without clear energy pathway distinction.

Final answer: C