If a gauge shows 350 kPa, what is the absolute pressure?

To determine absolute pressure from gauge pressure, it is important to understand the difference between these two types of pressure measurements. Gauge pressure is the pressure relative to atmospheric pressure, which means it does not account for the weight of the atmosphere acting on the fluid. Absolute pressure, on the other hand, is the total pressure including atmospheric pressure.

In your case, if the gauge shows 350 kPa, this value is above atmospheric pressure. To convert gauge pressure to absolute pressure, you typically add the atmospheric pressure, which at sea level is approximately 101.3 kPa. Thus, the calculation would be:

Absolute Pressure = Gauge Pressure + Atmospheric Pressure

Absolute Pressure = 350 kPa + 101.3 kPa = 451.3 kPa

Rounding to the nearest whole number gives you 451 kPa. That is why the correct answer is 451 kPa; it accurately reflects the conversion from gauge pressure to absolute pressure, accounting for atmospheric influences.