Thermometer offset error cancels in temperature differences

Steps:

• Thermometer reads 1°C at actual 0°C (ice point) and 101°C at actual 100°C (boiling point), showing a consistent +1°C bias.
• For initial water temperature T1°C actual, reading is T1 + 1°C.
• After heating to T2°C actual, reading is T2 + 1°C.
• Calculated rise: (T2 + 1) - (T1 + 1) = T2 - T1, matching actual rise.

Why B is correct:

• Temperature differences are unaffected by uniform scale errors, per the principle that additive biases cancel in subtractions.

Why the others are wrong:

• A: Ignores bias cancellation; rise isn't lowered.
• C: Assumes non-cancelling error, but +1°C offset applies equally.
• D: Mistakenly doubles the error without recognizing subtraction.

Final answer: B