CBSE > Class 12 > Physics | CBSE Board | Homework Help

E=-∆V/∆l Signficance:- 1. Electric field is in the direction in which potential decrease steepest. 2. The magnitude of the electric field is equal to the change in potential per unit perpendicular distance between two equipotential surface.

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Derive a expressio for potential energy of two charges placed in an external field

Posted by Goldi Pandey 6 years, 3 months ago

CBSE > Class 12 > Physics

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A network of capacitors where the number indicates capacitances in microfarad. Find the value of capacitance if the equivalent capacitances between points A and B is to be 1microfarad.

Posted by Eva Leivon 6 years, 3 months ago

CBSE > Class 12 > Physics

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What is OERSTED'S EXPERIMENT?

Posted by Vaibhav Kaushik 6 years, 3 months ago

CBSE > Class 12 > Physics

2 answers

Yash Rawat 6 years, 3 months ago

1-Orested stated that static charge produce electric field 2-But moving charge creates mag as well as electric field 3-He state that mag. Field is denote d by B

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Yash Rawat 6 years, 3 months ago

Orested prepared a circuit and connected a reistor in it. Then he used a magnetic compass and when he placed it near the resistor there was deflection in it

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vector form of coulombs law

Posted by Abhishek Raghuwanshi 6 years, 3 months ago

CBSE > Class 12 > Physics

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S.....Sharma☺??? .. 6 years, 3 months ago

F12=force on charge q2 due to q1 =Kq1q2 r cap 12/r^2

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Find 1st member & last member of lyman series on hydrogen spectrum?

Posted by Smart Rj 6 years, 3 months ago

CBSE > Class 12 > Physics

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In a wire current is flow 5mA

Posted by Ashwani Chauhan Chauhan 6 years, 3 months ago

CBSE > Class 12 > Physics

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How to best improvement in physics for class 12

Posted by Vijay Jadon Vijay Jadon 6 years, 3 months ago

CBSE > Class 12 > Physics

1 answers

Mithlesh Prajapati 6 years, 3 months ago

Firstly do not take burden of this subject. divided the full syllabus into some small part And complete one part and revised it and take a question of that part and solve all then ,go to another part . One things mention it that you follow one book that's you like or understood easily.

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What is Charging by polarisation?

Posted by Rampravesh Kumar 6 years, 3 months ago

CBSE > Class 12 > Physics

1 answers

Yogita Ingle 6 years, 3 months ago

When a dielectric slab is placedin an electric field, then the dipole moment is gained by the molecule and the dielectric is said to be polarised.

The Electric Polarization is dipole moment per unit volume of a dielectric material.

The polarization is denoted by P.

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What are electromagnetic waves

Posted by Sanjeev Sanjeev 6 years, 3 months ago

CBSE > Class 12 > Physics

1 answers

Gaurav Seth 6 years, 3 months ago

The waves which do not require a material medium for their propagation are called electromagnetic waves. Such waves travel through vacuum with a speed of 3 x 10⁸ m/s.

Examples of electromagnetic waves :

(i) Light waves

(ii) X-rays

(iii) Radiowaves

(iv) Microwaves.

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Explain the mechanism of flow of flow of electric current in a conductor.

Posted by Anshika Mishra 6 years, 3 months ago

CBSE > Class 12 > Physics

1 answers

Sunil Chaurasia 6 years, 3 months ago

By Substitution of charge .one charge push another charge.

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What are free and bound charge ? Definition.

Posted by Veena Singh☺️? 6 years, 3 months ago

CBSE > Class 12 > Physics

3 answers

Yogita Ingle 6 years, 3 months ago

In metallic conductors, electrons of outer most shell of the atoms are loosely bound to the nucleus. On applying electric field, they get detached from the atom and move freely inside the metal. These freely moving electrons are called free charges.
The positive charges consist of nuclei and electrons of inner shells are held stationary. These immobile charges constitute the bound charges.

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Veena Singh☺️? 6 years, 3 months ago

????

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Akhileshwar Singh 6 years, 3 months ago

When an electron leaves an atom the atoms become positively charged ion these positively charged ion remain held in their fixed position.

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An elevator that ascends from the lobby to the 36th floor ,stops, descends to the 27th floor,stops and returns to the lobby.Sketch tje displacement time graph, velocity time graph and acceleration time graph.

Posted by Ashish Chandel 6 years, 3 months ago

CBSE > Class 12 > Physics

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Why the current should not be passed through a potentiometer wire for a long time???

Posted by Vishakha Dixit 6 years, 3 months ago

CBSE > Class 12 > Physics

1 answers

Vishal Kumar 6 years, 3 months ago

bec. Heating effect of current will occur on it's wire and wire get heated and its resistance changes

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A screen is placed 90cm from an object.

Posted by Lovelesh Debnath 6 years, 3 months ago

CBSE > Class 12 > Physics

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The equivalent wavelength of a moving eletron has the same value asthat of a proton of energy 6×10power-17th. Calculate the momentum of electron?

Posted by Rajat Kumar 6 years, 3 months ago

CBSE > Class 12 > Physics

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In a neutral sphere, 5× 10^21 electrons are present. If 10 percent elections are removed, then calculate the charge on the sphere.

Posted by Shital Gupta 6 years, 3 months ago

CBSE > Class 12 > Physics

1 answers

Nishu Sahu 6 years, 3 months ago

Charge on sphere = 5×10^20×1.6×10^-19 = 80 C

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A hollow spherical conductor having radius R and charge on it Q and a small charge q is placed at the centre of the sphere . find the work done in bringing the charge q to suface of sphere

Posted by Piyush Kishore 6 years, 3 months ago

CBSE > Class 12 > Physics

1 answers

Shatayu Ganvir 6 years, 3 months ago

Apply here {v2-v1}×q ie. But v2=v1 Therefore.. Work done is zero

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The number of electrons in one coulomb of charge is

Posted by Gourav Kumar 6 years, 3 months ago

CBSE > Class 12 > Physics

1 answers

Yogita Ingle 6 years, 3 months ago

We know that the a electron have charge of 1.6 × 10⁻¹⁹ C
∴ e =1.6 × 10⁻¹⁹ C
Total charge required 1 Coulomb.
∴ q = 1C
Since q=ne
⇒ n =q/e
⇒ n = 1/1.6 × 10⁻¹⁹
⇒= 6.25×10¹⁸
⇒ n = 6×10¹⁸ electrons.

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Books for boards??

Posted by Aryan Gupta 6 years, 3 months ago

CBSE > Class 12 > Physics

2 answers

Nishu Sahu 6 years, 3 months ago

Sl arora and ncert

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Sajid Ali 6 years, 3 months ago

NCERT

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Kichoff law

Posted by Neeraj Yadav 6 years, 3 months ago

CBSE > Class 12 > Physics

1 answers

Sahil Kumar 6 years, 3 months ago

Kirchoff law states two laws basically which is used mainly in determing the division of current flowing through the Circuit Ist law-- Law of conservation of charge. Mathematically-- Ei=0 (E defines sigma) And i for current IInd law--- law of conservation of energy Mathematically- E V=0 (V for potential difference)

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Friends by what time we should complete our 12th board syllabus to score a very good percentage??????? Pls answer it.

Posted by Kumar Vishal Behera 6 years, 3 months ago

CBSE > Class 12 > Physics

9 answers

Kumar Vishal Behera 6 years, 3 months ago

Thanks priya. Best of luck.

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Priya Dharshini 6 years, 3 months ago

By second week of october u need to complete the portion or at max before diwali vacation.... then onlu you can concentrate on competitive exams and practicals,pre boards etc...

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Kumar Vishal Behera 6 years, 3 months ago

Thanks alok. Best of luck.

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Alok Kumar Shah 6 years, 3 months ago

I think December and then only practice set daily. I think this is better because 12th syllabus is vast and if we first read all the topic with our concern without any pressure and then in last time we only prepare for exam. This is my opininon and I think this work. Without any pressure just first complete your book with all the question doubt question and in last time just solve pratice set.

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Kumar Vishal Behera 6 years, 3 months ago

Ok sajid complete your syllabus by August ok hope to see ur name Sajid ali- 99.8% marks 499/500. best of luck.

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Sajid Ali 6 years, 3 months ago

August

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Kumar Vishal Behera 6 years, 3 months ago

I guess November is the correct time. But thanks Manesh and Anisha.

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Manesh Tandel 6 years, 3 months ago

Oct