Question

If two temperatures differ by $25$ degrees on Celsius scale, the difference of temperature on Fahrenheit scale is:
A. ${65^ \circ }$
B. ${45^ \circ }$
C. ${38^ \circ }$
D. ${25^ \circ }$

Answer 1

Originally, by setting zero, the Celsius temperature range was specified as the temperature at which water freezes. The temperature at which ice melts was later redefined as Zero degrees Celsius. The other point at which Celsius was formed, $100$ degrees Celsius, was described as the water's boiling point.

Complete answer:
Fahrenheit is a temperature scale mainly found in the United States, where the water freezing point is $32$ degrees and the water boiling point is $212$ degrees. This divides $180$ degrees from the boiling and freezing points of water. Thus, a degree on the scale of Fahrenheit is $1/180$ of the interval between the freezing point and boiling point. The freezing and boiling points of water are $100$ degrees apart on the Celsius scale. A ${1^ \circ }F$ temperature interval is equal to a $5/9$ degrees Celsius interval.

Each degree Celsius is equivalent to ${\dfrac{5}{9}^{th}}$ of a degree Fahrenheit.
Each degree of Fahrenheit equals ${\dfrac{9}{5}^{th}}$ of one degree of Celsius.
In Celsius, a $25$ degree difference will be $25 \times \dfrac{9}{5} = 45$ degrees Fahrenheit.

Hence, option B is correct.

Additional information:
Ice point temperature- The temperature under atmospheric pressure at which liquid and solid water is in equilibrium. For determining temperature ranges and for calibrating thermometers, the ice point is by far the most critical fixed point. Freezing point is where a liquid becomes a solid at a temperature. As with the melting point, the freezing point is normally raised by added pressure. In the case of mixtures and for some chemical compounds including fats, the freezing point is smaller than the melting point.

Note: Here we have to multiply $\dfrac{9}{5}$. If we multiply $\dfrac{5}{9}$ instead of $\dfrac{9}{5}$, then the answer would be wrong. Also we may be confused between the options so we have to be careful.