Question

In an oil-cooled transformer, why is cooling oil introduced at the bottom and allowed to rise?

Options

• Heated oil becomes lighter and rises carrying heat upward

• Cold oil is lighter than hot oil

• To prevent convection currents

• Oil cannot move downward when heated

Answer 1

Heated oil becomes lighter and rises carrying heat upward

Explanation:

When oil absorbs heat its density decreases, so it rises and carries heat to the tank walls for cooling.