Which one of the following statements with regard to expansion of materials due to heating is not correct ?
[amp_mcq option1=”As ice melts, it expands uniformly up to 4°C.” option2=”Mercury thermometer works using the principle of expansion due to heating.” option3=”Small gap is kept between two rails to allow for expansion due to heating.” option4=”The length of metallic wire increases when its temperature is increased.” correct=”option1″]
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.