What causes the tube of a C type Bourdon tube to attempt to straighten?

The correct choice is related to how a C type Bourdon tube operates in the context of pressure measurements. A Bourdon tube is a mechanical device used to measure pressure. It consists of a curved, elastic tube that tends to straighten as internal pressure increases.

When pressure is applied inside the tube, it creates a force that acts to expand the tube, causing it to straighten out from its curved position. This mechanical movement is then translated into a measurement readout, often seen on a dial gauge. In this way, the tube effectively converts the pressure exerted on it into a mechanical motion that can be quantified.

The link between the tube's behavior and pressure is fundamental to how pressure gauges function. While temperature, flow rate, and voltage may impact different instruments, they do not directly cause the Bourdon tube to attempt straightening in the same way that pressure does. Understanding this mechanism is crucial for anyone working with pressure measurement devices.