# Vectors And Scalars

In this lesson I will describe vectors and scalar quantities , their differences and different types of vectors including unit vectors.

Some physical quantities can be completely described with a single number such as time, weight, length etc. These quantities are called scalar quantities. But in some cases only a single number is not enough. Suppose, your home is 5 km north from your school. Someone asked you about your home’s location, and you said that your house is 5 km away from your school. If he wants to find your home, there are infinitely many options for him. He…

# Electric Dipole

An electric dipole is a pair of positive and negative charges with equal magnitude and separated by a small distance. For example, two opposite charges +q and -q having a distance d between them is a dipole.

Example of an electric dipole is hydrogen fluoride (HF) gas. HF is a covalent compound. Hydrogen and Fluorine both share their electrons. But fluorine has a greater tendency of attracting electrons than hydrogen, so fluorine pulls the shared electrons towards it and HF becomes a polar molecule. The Fluorine molecule becomes negatively charged and the Hydrogen molecule becomes positively charged. …

# Faraday Cage : Why Are Cars & Planes Safe From Lighting

Have you ever wondered if you could survive if you were struck by lightning while you were in your car? In fact, most of the cars are safe from lighting. In this article I will discuss about why are cars and planes safe from lighting and how does electrostatic shielding work.

A car or a plane which has a full metal body essentially acts as a Faraday Cage. In order to understand what is a Faraday Cage, lets dive into electrostatics.

If a conductor is placed in an external electric field, the net electric field inside a conductor always remains…

# Equipotential Surface : Why Is The Electric Potential Same Everywhere Inside A Conductor

Electric potential of a point is the work done by electric force to bring a 1 coulomb positive charge from infinity to the point. Suppose, the potential of point A near the charge q is 5 volt. This means if you bring a 1 coulomb positive charge from infinity to point A, you have to do 5 J work against the repulsive force of the charge q. Because, both charge will repel each other.

As electric force is a conservative force, the work doesn’t depend on which path you choose to bring the charge from infinity to point A. This…

# Work Energy Theorem : Classical Mechanics

If you push a stationary car, the car will start moving. That means, the car has gained some velocity. We say that the car has gained some kinetic energy. Kinetic energy is the energy associated with velocity of an object. You have to do some work to push the car and work is a kind of energy. But energy cannot be destroyed. So this work is converted into another type of energy.

According to the work energy theorem, this work is converted into the kinetic energy of the car.

Let the mass of the car is m and its initial…

# Electric Potential & Electric Potential Energy

In this article I will discuss briefly about electric potential energy, electric potential , derive formula for them and will also discuss the difference between the two terms.

# Potential energy

Potential energy is the energy that is stored in an object and later the energy can be converted into another form of energy like kinetic energy. If an object falls from a height, it will gain kinetic energy when it hits the ground. Because the gravity will cause the object to speed up.

When an object with mass m falls from a height h, the work done by the gravity is =…

# Central Limit Theorem In Statistics

In this article I will discuss about Central Limit Theorem intuitively with examples and also give an intuition behind the central limit theorem formula.

Let we have a large number of population and we have a probability distribution of their daily income. According to the statistics, about 40% of them earn on average 100\$ per day, 20% of them earn 200\$ and the rest 40% of them earn 300\$ per day.The following picture shows the probability distribution of the daily income of the population.

Clearly, this is not a normal probability distribution. The expected value of the probability distribution is…

# Dielectric Material : How Does The Electric Field Inside A Dielectric Decreases

In this article I will discuss briefly about dielectric material, dielectric constant, electric permittivity and how does coulomb’s law change in different dielectric mediums.

According to coulomb’s law, if two positive charges q0 and q are placed in an empty space and the distance between them is r, they will repel each other. The magnitude of the repulsive force is ,

The electric field E is the coulomb’s force on unit charges. That is , the coulomb’s force if q = 1.

# Conditional Probability

In this article I will discuss about dependent events , independent events , formula for conditional probability and some examples.

# Dependent Events

Let us begin with an example. Suppose, we have a bucket filled with 8 balls. 5 of them are green and 3 of them are blue.

Let , we randomly pick up two balls one by one without replacement. Let us define two events :

A : First ball is green

B: Second ball is blue

Now, the probability of getting a green ball on first step = P(A) = 5/8. Because, we have 8 possible cases and there are…

# Electric Field Between Two Charged Plates

In this article we will use Gauss’s law to measure the electric field between two charged plates and the electric field of a capacitor.

Gauss’s Law states that :

The net electric flux through any hypothetical closed surface is equal to (1/ε0) times the net electric charge within that closed surface

Let we have a charged plane of infinite length and width. And let positive charges are equally distributed throughout the surface.

Though the plane in the picture doesn’t have infinite length and width , let us assume this as an infinite plane.

Let the charge density on the surface…

## Farhan Tanvir Tushar

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