Question

The type of braking system referred to as power brake use of
$\left( {\text{A}} \right)$ Electromagnets
$\left( {\text{B}} \right)$ Compressed air
$\left( {\text{C}} \right)$ Vacuum
$\left( {\text{D}} \right)$ Compressed water

Answer 1

-Power brakes are a system of Hydraulics that are used to stop motor vehicles.
-The hydraulics braking system works by pressure on the fluid inside a motor vehicle and that creates an air compression brake.

Complete step by step answer:
The power brake system is a part of the Hydraulics brake that used to stop or slow down motor cars. The working principle of the Hydraulic brake is based on the application of the principle of multiplication of thrust from Pascal’s Law.

To stop a car force is applied by the driver on the padel and hence the brake oil of the master cylinder is faced with pressure on it. This pressure pushes the pistons by flowing through the wheel cylinder. Then the brake shoe that is attached to the piston is pressed on the rim of the wheel and gradually stops.

So, here the air is compressed within due to the pressure created on the piston.
Hence the right answer is in option $\left( {\text{B}} \right)$.

Additional information:
A compressed air brake system those are used in large vehicles such as trucks, buses, trailers, and semi-trailers, or railroad trains having multiple trailers, is a type of friction brake for vehicles in which compressed air that pressed on a piston is used to apply the pressure to the pedal to stop or slow down the vehicle. Air brakes are the trailers linked to the brake system.

This Air brake is an alternative to the Hydraulic brake.

Note: Powered by the vehicle’s engine the compressed air by the piston applies a normal pressure and forces it in a very small space.
Hence the pressure of the air increases.
Therefore the compressed air also becomes a form of energy storage.