Question

Two thermometers X and Y have ice points marked at ${15}^{\circ }$ and ${25}^{\circ }$ and steam points marked as ${75}^{\circ }$ and ${125}^{\circ }$ respectively. When thermometer X measures the temperature of a bath as ${60}^{\circ }$ on it, what would thermometer Y read when it is used to measure the temperature of the same bath?

• A. ${60}^{\circ }$
• B. ${75}^{\circ }$
• C. ${100}^{\circ }$
• D. ${90}^{\circ }$

Answer 1

The correct option is C ${100}^{\circ }$


Using scale conversion,
we can write
$\frac{X-{15}^{\circ }}{{75}^{\circ }-{15}^{\circ }}=\frac{Y-{25}^{\circ }}{{125}^{\circ }-{25}^{\circ }}$
Given, $X={60}^{\circ }$
$\frac{{60}^{\circ }-{15}^{\circ }}{{75}^{\circ }-{15}^{\circ }}=\frac{Y-{25}^{\circ }}{{125}^{\circ }-{25}^{\circ }}$
$\frac{{45}^{\circ }}{{60}^{\circ }}=\frac{Y-{25}^{\circ }}{{100}^{\circ }}$
$Y={100}^{\circ }$

Why this question? Temperature is a measure of the amount of heat energy possessed by an object. As temperature is a relative measurement, scales based on reference points must be used to accurately measure temperature