High-voltage transmission minimizes energy loss over long distances

Steps:

• Identify typical voltages: bicycle dynamo (6-12V), household lighting (120-240V), inter-town power lines (up to 400kV), cooker cable (240V).
• Compare magnitudes: low for A, moderate for B and D, very high for C.
• Select highest: C exceeds others by orders of magnitude.
• Confirm context: question focuses on transmission voltage, not current or power.

Why C is correct:

• Power cables between towns use high voltage (e.g., 132-765kV) to reduce I²R losses in transmission lines, as per the power transmission formula P = VI, where high V lowers I for fixed P.

Why the others are wrong:

• A operates at low voltage (6-12V) for small-scale, short-distance DC power.
• B carries standard mains voltage (120-240V AC) for home use.
• D uses household voltage (240V AC) for appliances, not long-distance transmission.

Final answer: C