Question

The lower fixed point on the Celsius scale is:
A. Melting point of ice
B. Boiling point of water
C. Melting point of mercury
D. Mean of melting point and boiling point of water

Answer 1

Firstly remember that Celsius scale is one the scales used to measure temperature. Then you could remember the temperature range of this scale and thus identify the lower and higher fixed points. After that you could see which of the given options is represented by the lower fixed point of Celsius scale.

Complete answer:
In the question, we are asked to find which of the following options is represented by the lower fixed point on the Celsius scale.
Basically, we use three different scales for measuring temperature. Celsius scale is one among them. We know that the Celsius scale is known to range from $0{}^\circ C$ to$100{}^\circ C$. Therefore, we see that the lower fixed point of Celsius scale is $0{}^\circ C$. Here, you may recall that $0{}^\circ C$ is the temperature at which the ice melts and water freezes. So from the given options we could say that, the lower fixed point on the Celsius scale is the melting point of ice.

Hence, option A is found to be the correct answer.

Additional information:
The other two temperature scales that we use are the Kelvin and Fahrenheit. The Fahrenheit scale which has 180 divisions varies from $32{}^\circ F$ to $212{}^\circ F$, where $32{}^\circ F$ is the melting point of ice. In the Kelvin scale the melting point of ice or the freezing point of water is found to be at $273.15K$.

Note:
The higher fixed point of Celsius scale which is $100{}^\circ C$ and is known to be the temperature at which water boils. If we were to measure the body temperature, it would be $37{}^\circ C$ in Celsius scale and $98.6{}^\circ F$ in Fahrenheit scale. If the temperature is found to be over $100.4{}^\circ F\left( 38{}^\circ C \right)$ then we could say that the person suffers from fever.