Work

Definition:-

"Work is the product of force and the distance covered by a body due to force applied on it"

Explanation:-

In physics work is done on a body, when we apply some force on it and it covers some distance in the direction of force.

Work is not done until body is not covering some distance whether force is applied on it or not, body has to cover some distance in order to get work done. or work will not be done until force will not be apply on it whether it is covering some distance or not. so both things are necessary.

Example:-

1.When you try to push the box by applying force on it and box start to move in direction of force, then your are doing work.

2.When you try to push the wall then you apply force but wall doesn't move, so you are not working (According to physics).

Unit:-

The Sl unit of work is joule J

Formula:-

Work also have an formula to calculate it mathematically,

W=F.d.cosθ

As define work is the product of force and distance and the angle between them. 

Conditions:-

1.This cos shows that when force applied and distance covered is in same direction then angle will be 0, where cos(0)=1, hence work will be maximum.

2. When force applied and distance cover will be perpendicular to each other than angle will be 90 and cos(90)=0, hence work will be 0.

3. When force applied and distance covered is in opposite direction  then work will be negative as, angle will be 180 and cos(180)=  -1.

AC Generator

Definition:-

"The machine which is used to convert mechanical energy into electrical energy(AC current) is known as AC Generator"

Explanation:-

The device which gives us AC current(Electrical energy) by taking mechanical energy from any source(could be us) is known as Ac generator. Its construction is similar to dc generator and its working is also same almost. 

The above shown diagram is of AC generator. our need is to get the current which changes its direction after every half cycle, so to get this we need to get the current from one slip ring for one half and for other slip ring for the second half. Slip rings are connected at different ends of closed circuit. where load is connected. So that load will get Ac current.

Construction:-

It consists of following parts:-

1.Magnet

2.Slip Rings or Commutator

3.Conducting Coil or Armature

4.Carbon brushes

5. Load  

Working:-

According to the Faraday's Law of electromagnetic induction, whenever a conducting coil is move or rotates across magnetic field emf produces in it and due to this, current starts to flow through it. So in this generator when coil will move by some mechanical force across magnetic field of magnet, then there will produce an EMF and because of this, current will start to flow through it(if coil path is closed or connected to other circuit). Direction of current will be according to Fleming's right hand rule. 

As shown in this diagram, For first half rotation of coil the current will go to the load form one slip ring and for 2nd half rotation of coil the current will go from the other slip rings to the load so it is giving ac current to the load as it is changing its direction after every half cycle.

Generator(DC)

Definition:-

"The device which converts mechanical energy into electrical energy is known as Generator."

Explanation:-

Generator use to produce electrical energy from mechanical energy for our purpose.

Above shown diagram is of DC generator, its construction is same as Electric motor(DC), the difference is that from where we give input in input, from there we get output from generator. the mechanical energy could of any type. for example moving pivot with your hand and by some other source.

Construction:-

It consists of:-

1.Magnet

2.Conducting Coil loop

3.Commutator

4.Carbon brushes

5.Battery

Working:-

According to Faraday's law, whenever a conducting coil will move across magnetic field then there will produce an EMF, and due to this, current will start to flow through coil (if path is closed). the direction of current will be according to Fleming's Right hand rule(Described below). Then this current will go through commutator and through carbon brushes it will go through battery and will charge. That its simple working!

Faraday's Law of electromagnetic induction:-

This law state's that" whenever a conducting coil is move across the magnetic field of magnet, then EMF will produce in coil and current will start to flow through it" Current direction would be according to Fleming right hand rule.

Fleming's Right hand rule:-

According to this law "Straighten your thumb, fore finger and middle finger so that they become perpendicular to each other(right angle to each other) and then your thumb will represent the coil, your fore finger will represent the magnetic field and your middle finger will represent the direction of current flow."

Electric Motor(AC)

Definition:-

"An electric device that converts an AC electric source into mechanical energy is known as AC electric motor"

The device that converts Electrical energy into mechanical energy for our use, we called that device electric motor.

Explanation:-

The above diagram is of ac motor that converts an ac source into mechanical energy. The problem we face in ac motor is that, ac current changes its direction after half cycle. So it is not possible for conducting coil to move in one direction for complete cycle of  ac current. To overcome this problem, we use split rings instead of commutator, so that we could reverse the direction of current. and coil could move in one direction.

Construction:-

It consists of,

1.Magnet

2.Conducting loop

3.Split rings

4.Carbon brushes

5.Ac source

Working:-

AC motor works on the same principle, as DC motor works. When we connect ac current source to the carbon brushes then through split rings current starts to flow through the wire( or conducting loop) so because there is also magnet field through wire and now current flowing through it, So according to Fleming's left hand rule, the coil will start to move. When ac current will change its direction split rings will change their direction and so coil will get same directed current and coil will move in one direction.

Electrical Motor(DC)

Definition:

"Electric motor is a device that converts electrical energy to mechanical energy"
The device which converts electrical energy into other form of energy which is mechanical energy so that we can take benefit from it.

Types of Motor:

There are two basic types of electric motor:-

1.DC motor

2.AC motor

 

DC motor Explanation:

The motor which converts DC power to the mechanical energy or power is known as dc motor.

Above diagram is of dc motor. It consists of a magnet, armature or conducting loops, carbon brushes, commutator, dc source or battery.

Working:-

When we connect the battery with the carbon brushes than through commutator they cause the current to flow through loops, as on the other hand there is also magnetic field from north to south so as we have studied Fleming's left hand rule(will explain below), the loops will move upward from one side and will move downward from other side. When this current carrying conductor(conducting loops) will change position at 90 degree than again according to the Fleming's rule this loop will move as it is going. So that how it works. other end of loop would be connected with the object to whom we want to provide mechanical energy. 

Fleming's Left hand rule:-

This rule states that" hold your left hand and tied your 1st finger, 2nd finger and thumb in such a way that they each other become perpendicular(Right angle) to each other. now if first finger is the direction of magnetic field and 2nd finger represent the current flowing through coil, then thumb will represent the force acting on it." 

Centripetal force

Definition:

"Centripetal force is a force, which keeps a body moving in a circular path and that force acting towards the center of that circular path."

Explanation:

A body never automatically or itself moves in a circular path it, there is always a reason or some force that causes it to move in a circular path and that force in general is known as a centripetal force. and that force is always directed towards  center. it means force is from the center of circular path that causes it to move in a circular path.

Example:

You tries to move a string in a circular path. one end of it is in your hand and other is tied with a stone. and consider that stone is a body. you provide force from your hand which is at the center of circular path in which stone(body) is moving.

Formula:

 

This equation shows that force depends on the mass of body and the velocity by which it is moving in path and the distance(r) between the center of circular path and body.

What is Force?

Definition:-

"Force is a reason or something that causes the change in a motion or situation of a body."

Explanation:

Force is the reason which causes change, if you want to move something or you want to do some work you have to apply force.
A force is a vector quantity. a vector quantity is a quantity that has both magnitude and direction.




Unit:

Force is a quantity that is measured using the standard metric unit known as the Newton.  
1 Newton = 1 kg • m/s2

Formula:

According to the newton second law of motion, force is the product of mass and acceleration. Means force depends on mass and acceleration of body.It means that if a body has change in its velocity(speed) or position, then its depend upon the total force acting upon him and the mass of the body. It is also known as law of inertia. Having low mass will demand less force for change in its speed.
F=m.a

What is motion? Types of motion

Motion:-

When a body does not change its position with time it is said that it is in rest but when it changes it is called that body is in motion.

Types of Motion:-

There are few basic types of motion:

1. Translational motion

2. Rotational motion

3. Random motion

4. Circular motion

Translational:-

A body covering some distance while moving whether it is on straight line or curved line, but distance covering is necessary. it is known as translational motion.

i.e. You driving a car towards your destination the road sometimes will not be straight turns will come but you will cover distance.

Rotational:-

A body moving on its axis and its all parts have different directions. no matter in which direction it moves but move on its axis is known as rotational motion.

i.e. A beblayde moving on its axis, a fan blades moving.

Random Motion:

When a body moves randomly, it is known as random motion.
Random motion means when body doesn't follow a specific path just a zig zag type path to move then this movement is known as random motion.

i.e. Fly, Mosquitoes etc,  flying around you randomly is an example of random motion.

Circular Motion:

When a body moves in a circular path, it is known as circular motion.

it is simple type of motion when body moves in a closed circular path it is known as circular motion.

i.e. a racing car moving on a circular racing track.

Linked list

Linked list

Definition:

a linked list is a linear collection of data elements, in which linear order is not given by their physical placement in memory. Each pointing to the next node by means of a pointer. It is a data structure consisting of a group of nodes which together represent a sequence

Explanation:

A linked list is a linear data structure where each element is a separate object.

Each element of a list is comprising of two items - the data and a reference to the next node. The last node has a reference to null. The entry point into a linked list is called the head of the list. It should be noted that head is not a separate node, but the reference to the first node. If the list is empty then the head is a null reference.

A linked list is a dynamic data structure. The number of nodes in a list is not fixed and can grow and shrink on demand. Any application which has to deal with an unknown number of objects will need to use a linked list.

There are some figures below to explain Linked list.