It works on the principle of Pascals law.
Pascal's law: Pressure on a confined fluid is transmitted undiminished and acts with equal force on equal areas and at 90 degrees to the container wall.
Uses of hydraulic press - Hydraulic presses are commonly used for forging, clinching, moulding, blanking, punching, deep drawing, and metal forming operations.

Answer is B.
Hydraulics is the use of a liquid under pressure to transfer force or motion, or to increase an applied force. The pressure on a liquid is called HYDRAULIC PRESSURE. And the brakes which are operated by means of hydraulic pressure are called HYDRAULIC BRAKES. These brakes are based on the principle of Pascals law. 
The Pascal law states that 'The pressure exerted anywhere in a mass of confined liquid is transmitted undiminished in all directions throughout the liquid'.

The answer is A.

Pressure is the amount of force acting per unit area. That is, P=F/A.
where:
p is the pressure,
F is the normal force,
A is the area of the surface on contact. Let us consider A = $\pi { r }^{ 2 }$.
Therefore, $\dfrac { { F } _{ 1 } }{ { \pi { r } _{ 1 } }^{ 2 } } =\dfrac { { F } _{ 2 } }{ { \pi { r } _{ 2 } }^{ 2 } } $.

Hydraulic press works on Pascal's principle, which states - “pressure throughout a closed system is constant.” 

hydraulic brakes are based on the pascal`s law and is used for amplifying the applied force to a given extent .

A hydraulic lift is used to lift or support heavy objects. It consists of two pistons of variying cross sectional areas.

A hydraulic press is a mechanical machine used to lift or compress large loads. A hydraulic press consist of two cylinders $C _1$ and $C _2$, fitted with pistons, valves and tubes.

Hydraulic brake confirms to Pascal's law and is used in automobiles. It consist of a master cylinder filled with brake oil and provided with an airtight frictionless piston.

In the construction of hydraulic press, release valve and press foot valves are there.

Discharge of centrifugal pump is inversely proportional to square of the diameter of its impeller, thus option B is correct.

Hydraulic jacks works on the Pascal's law that the pressure in closed container is the same at all points.

Power required to drive a centrifugal pump is directly proportional to the fourth power of the diameter of its propeller.

The center of pressure of surface subjected to fluid pressure is the point on the surface at which gravitational force acts

The axial pump is a pump in which fluid flows axially to the rotation of the propeller. In Axial flow, the fluid flows parallel to the axis of rotation, as in a turbine. Axial flow pump contains a propeller or centrifugal impeller in the casing. Axial Flow pump is preferred for flood control and irrigation applications.

Slip of a reciprocating pump is defined as  Difference of theoretical discharge and actual discharge.

Jacks can be categorized based on mechanical and hydraulic forces.

The shaft in the floor jack is horizontal. Hence option B is correct.

Hydraulic jacks use pump plungers to move oil through two cylinders.

Two types of hydraulic jacks are commonly used- bottle jacks and floor jacks.

It is true that an enclosed fluid under pressure exerts that pressure throughout its volume and against any surface containing it.

In the vacuum suspended system, the brakes are applied when atmospheric pressure is applied to one side of diaphram.

Force required        $F = PA$    

In a vacuum suspended unit, when the brakes are on , the piston and diaphragm has on both sides of it Atmospheric pressure.

Hydraulic jack is a device, works on the Pascal's law, used to lift heavy objects. 

Type of braking system referred to as power brakes makes the use of compressed air.

The piston in the master cylinder is connected by mechanical linkage to the Brake pedal in the hydraulic braking system.

Since in integral type of power brake, the diaphgram acts directly on the hydraulic piston in the multiplier unit which leads to the increase in further pressure.

In the power assisted kind of brake the bellows applies force to master cylinder piston through mechanical linkage. A mechanical linkage is an assembly of bodies connected to manage forces and movement.

Most brakes on cars now are what are called "Power" brakes, and driven by a hydraulic braking control system

An air compressor produces air for the brake system. Powered by the vehicle’s engine, the air compressor draws in air at normal pressure and forces it into a much smaller space, causing the pressure of the air to increase. This compressed air is a form of stored energy.

Atmospheric power brakes and vaccum suspended power brake are two classifications of vaccum assisted power brakes.

pressure for same liquid is $\rho gh$

$f=900 N$
$a=\pi \times (\frac {1.8}{2})^2=\pi \times \frac {(1.8)^2}{4}$
$A=\pi \times (\frac {36}{2})^2=\pi \times \frac {(36)^2}{4}$
Now $\frac {f}{a}=\frac {F}{A}$
$\Rightarrow \frac {900\times 4}{\pi (1.8)^2}=\frac {F\times 4}{\pi \times (36)^2}$
$\therefore F=\frac {900\times 4}{\pi \times 1.8\times 1.8}\times \frac {\pi \times 36\times 36}{4}$
$=36\times 10^4N$.

$\begin{array}{l} \dfrac { f }{ { 10 } } =\dfrac { { 1000 } }{ { 225 } }  \ f=\dfrac { { 10000 } }{ { 225 } }  \ f=44.44N \end{array}$

The hydraulic machine uses Pascal's principle, which states that states that the pressure exerted anywhere in a confined incompressible fluid is transmitted equally in all directions throughout the fluid.
The hydraulic machine is used to multiple force or to transmit force from one location to another. 
i)     hydraulic brakes
ii)    hydraulic press
ii)    hydraulic lift

We know that $P _{1} = P _{2}$

$\Rightarrow \dfrac{F _{1}}{A _{1}} = \dfrac{F _{2}}{A _{2}} $

$\Rightarrow \dfrac{A _{1}}{A _{2}} = \dfrac{F _{1}}{F _{2}}  = \dfrac{1}{30} $

$\Rightarrow  1:30 $

Answer is A.

Pressure is the amount of force acting per unit area. That is, $P=F/A$.
where:
$p$ is the pressure,
$F$ is the normal force,
$A$ is the area of the surface on contact. Let us consider A = $\pi { r }^{ 2 }$.
Therefore, $\dfrac { { F } _{ 1 } }{ { \pi { r } _{ 1 } }^{ 2 } } =\dfrac { { F } _{ 2 } }{ { \pi { r } _{ 2 } }^{ 2 } } $.
In this case, $\dfrac { 1500 }{ { 20 }^{ 2 } } =\dfrac { W }{ { 1 }^{ 2 } } ,\quad W\quad =\quad 3.75\quad kg.$
Hence, weight to be placed on the small piston sufficient to lift a car of mass 1500 kg is 3.75 kg.

To avoid vaporization in the pipe line, the pipe line over the bridge is laid such that it is not more than 6.4m above hydraulic gradient

Weight on the ram  $F  =  mg=1000\times 10 = 10000$

The maximum number of jets generally employed in an impulse turbine without jet interference are 6.

Using   $\dfrac{F _1}{A _1} = \dfrac{F _2}{A _2}$

The principle of similitude is a supplement to the scientific method advocated by Lord Rayleigh that requires that any suggested scientific law be examined for its relationship to similar law.

Hydraulic press is used in extraction of oil from oil seeds by crushing.