Skip to main content

Physics Notes on Electricity.

Electricity:

Electricity deals with the motion of the electric charge.Electric charge is a scalar quantity which unit is Coulomb.Electricity produced by the friction between two bodies is called static electricity or frictional electricitye.g. generation of electric charge on rubbing the plastic comb with dry hair.

Coulomb Law:

The magnitude of the electrostatic force of interaction between two charge points is directly proportional to the scalar multiplication of the magnitudes of charges and inversely proportional to the square of the distance between them.

Electric Field:

The space in the surrounding of any charge in which its influence can be experienced by other charge is called electric field.Electric field intensity (E) at any point is defined as the electrostatic force acting per unit positive test charge at that point. Its unit is Newton/coulomb.E=F/qElectric field intensity is inversely proportional to the square of the distance r from the point charge.

Electric Field Lines:

The electric field line is an imaginary lines or curve drawn through a region of space so that its tangent at any point is in the direction of the electric field vector at that point.Two lines an never intersect, electric field always start from the positive end and always ends on the negative charge and do not start or stop in the mid.

Electric potential:

The electric potential at any point in an electric field is equal to the work done per unit charge in carrying at least a test charge from infinity to that point. Its unit is joule/coulomb.The potential difference between two points in an electric field is equal to the work done per unit charge in carrying a positive test charge from one point to the other point.Potential difference decides the flow of charge between two points in the electric field.Positive charge always tends to move from higher potential towards lower potential.Inside the closed metallic body, the electric field is zero.

Electric current:

Electric current is the flow of charge with respect to time.Electric current=q/tAn electric current whose direction does not change with time is called direct current (D.C).An electric current whose direction changes with time is called alternating current (A.C).In solids- Current flow due to the flow of electrons 
In the liquid- Current flow due to the flow of ions as well as electrons 
In semiconductors- Current flow due to the flow of electrons and holes.

Resistance:

The resistance offered by any material in the flow of current is called as electrical resistance. Its S.I unit is ohm and [ML2T-3A-2] is its dimension.R=PL/AL=length of conductorA=cross sectional areaThe P= resistivity of the material.

Conductance

Conductance or conductivity is thereciprocal of resistance and the resistivity of the material respectively.Its SI unit is mho.

Resistivity

The resistivity of a material is equal to the electrical resistance of its wire unit length and of the unit area of cross-section.Its unit is ohm-meter.The resistivity of a material depends on the temperature and nature of the material.It is independent of dimensions of the conductor, i.e. length, area of cross-section.The resistivity of metals increases with increase in temperature.Resistivity is low for metals, more for semiconductors and very high for alloys.

Combination of Resistances

Resistance can be connected in two ways i.e. in parallel and in series.(a) Series
If resistance R1, R2 and R3 are connected in series their equivalent resistance is given by
R= R1+R2+R3
In series combination equal current flows through each resistor.(b) Parallel
If resistance R1, R2 and R3 are connected in parallel then equivalent resistance is given by.
1/R =1/R1 +1/R2 +1/R3

Ohm’s Law

It states that if physical conditions of any conductor such as temperature, pressure etc. remain unchanged then electric current(I) through it is directly proportional to the potential difference(V) applied across its ends. V=IR

Kirchoff’s Law:

Kirchoff current law: states that the net current on a junction in an electrical circuit will be zero. It is based on conservation of charge.

Kirchoff’s Voltage Law- states that the algebraic sum of all potential difference along a closed loop is Zero. It is based on conservation of energy.

Electric Cell:

An electric cell is a device which converts chemical energy into electrical energy.Electric cell is of two types:
(a) Primary cell: cannot be charged. Voltaic, Daniell and Leclanche cells are primary cells.
(b) Secondary Cell: can be charged again & again. Acid and alkali accumulators are secondary cells.

Joule’s Law of Heating

Joule heating describes the process where the energy of an electric current is converted into heat as it flows through a wire due to the resistance of the wire. Heat produced in the conductor due to electric current in time “t” is given byH=VIT=I2RT=V2t/rElectric bulb and heater work on the basis of the heating effect produced by the current.

Chemical Effect of Electric current:

When an electric current is passed through an acidic or basic solution, it decomposes into its positive and negative ions. The positive ions collect at the negative electrode(Cathode) and the negative ion is collected at the positive electrode (anode).This phenomenon is called electrolysis.

Faraday’s Law of Electrolysis

First law:

The total mass (M) deposited at an electrode in the process of electrolysis is directly proportional to the total charge (q) passed through the electrolyte.M=Zq, where Z is the electrochemical equivalent of the substance deposited at the electrode.

Second law:

If the same strength of the electric current is allowed to pass through different electrolytes for the same time, then mass deposited at the electrodes is directly proportional to their chemical equivalent.M1/M2 =E1/E2

Electric Power

P = V2/R = I2R

Here P= Electric Power, V= Voltage, R= Resistance

Electric Fuse

Used to preotect electric appliances from high current.Fuse wire made of the alloy of copper, tin and lead.The material of fuse wire should be low melting point and high resistance.

Shunt

It is the wire of very small resistance.If we add shunt parallel to galvanometer, then galvanometer act like an ammeter.
Note-
If we add high resistance in series with the galvanometer, then galvanometer act like a voltmeter.


Labels:

Comments

Post a Comment

"Welcome to my blog, where I, Sandeep Giri, share my passion for the Tech World. Join me on an exciting journey as we explore the latest trends, innovations, and advancements in the world of technology."

Popular Post

■ Can India Become A Technology Leader? India

  ■ Can India Become A Technology Leader?   ✅India is presently not a major player in the field of technology due to certain challenges and on the other side, there are many celebrated Indian technologists around the world as many of the technology giants choose an India- born techie as their leader. ✅The conversation around Indian executives at the helm of top tech companies has gathered some momentum with Parag Agrawal taking over as Twitter CEO. The major technology companies like Google and its parent company Alphabet, Microsoft and Twitter, Adobe and IBM are all headed by Indians. ● The Case of the U.S: ✅The Indian immigrants in the U.S are the part of the most educated and professionally accomplished communities in that country. ✅As of 2019, there were 2.7 million Indian immigrants in the U.S. ✅The government of the U.S has been instrumental in the triumphs of enterprise and the free market. ✅The governmental agencies have been actively supporting the research and develo...
Post a Comment
Read more

India stand with Taiwan..

1. India is set to take over as the next Chairperson of the World Health Organisation’s decision-making executive body 2. India will have to decide on supporting the USA’s move to reinstate Taiwan’s observer status at the World Health Assembly (WHA) that is opposed by China. 3. India’s nominee will take over as the Chairperson, replacing Japan. 4. India is likely to hold the post for the next three years. 5. The seven-nation meeting was attended by the foreign ministers of Australia, Brazil, India, Israel, Japan, and the Republic of Korea. 6. All invitees other than India are major non-NATO allies of the United States, who would be expected to support USA’s move. 7. China has been referring to the “One-China” principle as a widely accepted universal consensus of the international community including the Indian government.
Post a Comment
Read more

ISRO selected For Indira Gandhi Prize For Peace – 2014

Awards and Honours Manmohan Singh Received Japan’s Top National Award Former Indian Prime Minister Manmohan Singh was conferred with the “Grand Cordon of the Order of the Paulownia Flowers” Award on 5 November. The “Grand Cordon of the Order of the Paulownia Flowers” is perceived as the second highest civilian award of Japan after “Order of the Chrysanthemum”. The award was presented to Manmohan Singh by Japanese Emperor Akihito at the Imperial Palace in Tokyo. He was given this award for his “significant contribution to the enhancement of relations and promotion of friendship” between Japan and India. He became the first Indian to receive this prestigious award. West Bengal’s Darjeeling Zoo Selected For Earth Heroes Award 2014 The Darjeeling Zoo or the Padmaja Naidu Himalayan Zoological Park was on 1 November selected for the prestigious International Award The Earth Heroes Award 2014. It has become the first zoo in India. It has competed with 300 zoos across the world. Padmaja...
Post a Comment
Read more

Reset password without entered previous password .....

                  STEPS:- 1) Just open command prompt via administrator. 2) Type command "net user" to view all account of your pc. 3) Type command "net user <username> *" i.e. enter username of which you want to     change the password. 4) After entering command, a message occur "Enter your new password" & "Re-enter    your new password". & then command successful message occur.                               OR if you want to change the password in only one step:-   Type command "net user <username> <password you want to rest>             
Post a Comment
Read more

India Citizenship Amendment Act 2019

Protection of minors 1. There have been several instances of police clashing with and detaining protesters in the Anti-CAA protests. 2. In several cases, those detained were minors under 18 years. Detention of minors 1. Juvenile Justice (Care and Protection of Children) Act, 2015 has specific procedures and rules in relation to children found to be in conflict with the law. 2. As soon as a child alleged to be in conflict with law is apprehended by the police, the child is to be placed under the charge of the special juvenile police unit or the designated child welfare police officer. 3. That officer should produce the child before the Juvenile Justice Board within a period of 24 hours excluding the time necessary for the journey from the place where the child was picked up. 4. In no case should a child alleged to be in conflict with the law be placed in a police lock-up or lodged in a jail. NCPCR 1. National Commission for Protection of Child Rights (NCPCR) is a statutory bod...
Post a Comment
Read more

Follow the Page for Daily Updates!