Which one of the following statements with regard to expansion of materials due to heating is not correct ?
As ice melts, it expands uniformly up to 4°C.
Mercury thermometer works using the principle of expansion due to heating.
Small gap is kept between two rails to allow for expansion due to heating.
The length of metallic wire increases when its temperature is increased.
Answer is Right!
Answer is Wrong!
This question was previously asked in
UPSC NDA-1 – 2016
Most substances expand when heated, but water exhibits anomalous expansion between 0°C and 4°C. When ice melts at 0°C, it forms liquid water which is denser than ice. As liquid water is heated from 0°C to 4°C, it *contracts* and its density increases, reaching maximum density at 4°C. Only above 4°C does water expand like most other substances when heated. Therefore, the statement that water expands uniformly up to 4°C after melting is incorrect; it contracts from 0°C to 4°C.