According to Charles’ law, Volume of gas at t°C, $V_t$ = $V_0\left[1+\frac{t}{273}\right]$ (Since $V_0$ Volume at 0° C) Volume of gas at –273°C, V = $V_0\left[1-\frac{273}{273}\right]$ = 0 Thus, –273°C is the lowest possible temperature because below this temperature, the volume will become negative, and that is meaningless. This lowest temperature is called absolute zero temperature.