Question

A graph for an ideal gas at constant volume is plotted by taking pressure along y - axis and centigrade temperature along x - axis as shown in the figure below. Find the x intercept of the graph.

• A. $-273.15{}^{\circ }\text{C}$
• B. $-273.15\text{K}$
• C. $-273{}^{\circ }\text{C}$
• D. $-273\text{K}$

Answer 1

The correct option is A $-273.15{}^{\circ }\text{C}$

For an ideal gas at constant volume, pressure of a gas is proportional to the temperature i.e $P\propto T$
The pressure of a gas in $\left(\frac{\text{N}}{{\text{m}}^2}\right)$ becomes zero when the temperature (in Kelvin scale) becomes zero.
From the relation between Kelvin and Celsius scale,
$C=K-273.15$
We can conclude that, the x-intercept of the graph (when pressure is equal to zero) is $-273.15{}^{\circ }\text{C}$