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

Your question is not very clear.First,you shoud state the question very clearly and its given data. But,as i understood this question from my understslanding its correct answer shoud be 16uc

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Are additional questions in textbook are going to be in exam or not ?

Posted by Manav Bansal 6 years, 2 months ago

CBSE > Class 12 > Physics

4 answers

? Natasha Yadav? 6 years, 2 months ago

We can't predict anything, but why should you leave anything that is given in NCERT.

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Shivam Chaurasia 6 years, 2 months ago

In 2019 a question of additional has been asked from electromagnetic onduction , last 2 ques. Are very important.

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Řøhăň Řąjpůť ✌️✊ 6 years, 2 months ago

yes additional questions are imp. but not all only few questions are from examination point of u.. u should refer last year paper for rough idea regarding this questions.

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Priya Dharshini ? 6 years, 2 months ago

It will come in exam... u cant skip anything.. dont risk..

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A galvanometer of resistance 120 ohm gives full scale deflection for a current of 5ma how can it be converted into an ammeter of range 0 to 5 A ? describe the net resistance

Posted by Adarsh Maurya 6 years, 2 months ago

CBSE > Class 12 > Physics

1 answers

Divya Deep Srivastava 6 years, 2 months ago

By connecting 0.12 ohm resistance in parallel to tje galvanometer.

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What is the principle of wear stone bridge

Posted by Aasta Chouhan 6 years, 2 months ago

CBSE > Class 12 > Physics

1 answers

Ansh Preet 6 years, 2 months ago

It's wheat stone bridge.. Not wear stone nd it is used to find the resistance of any unknown resistor if we're given 4 resistors connected with a galvanometer nd a battery in which one resistor is variable other 2 are known nd one is unknown...

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How we will be best in physics

Posted by Tannu Madaan 6 years, 2 months ago

CBSE > Class 12 > Physics

2 answers

Shivam Chaurasia 6 years, 2 months ago

Whenever you are reading imagine as it happen infront of you every mechanism. It will provided you better concept.

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? Natasha Yadav? 6 years, 2 months ago

I have answered this same question in yesterday's question asked by Mamta Rani. You can refer there.

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Important question of chapter-4

Posted by Muskan Verma 6 years, 2 months ago

CBSE > Class 12 > Physics

2 answers

Priya Dharshini ? 6 years, 2 months ago

Do whole ncert question and theory and application based questions from this app and ncert or u can use sl arora.. and board questions. Cyclotron applications and principle and all about it, bohrs magneton derivations and many formule and numericals..

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Řøhăň Řąjpůť ✌️✊ 6 years, 2 months ago

we are appearing for boards so each and everything is important from examination point of view ncert questions + ncert back exercise + few selected questions from additional exercise nd these selected question can be easily found in sample papers.

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Do the following topics of 'moving charges and magnetism' are in 2019-20 syllabus?:- 1.circular current loop as a magnetic dipole. 2.magnetic dipole moment of a revolving electron.

Posted by Aradhya Trivedi 6 years, 2 months ago

CBSE > Class 12 > Physics

3 answers

Gurman Kaur 6 years, 2 months ago

Yuuppp

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Ďãřşháñăã Yadav ? ? ? 6 years, 2 months ago

yes they are in the syllabus nd considered as most important topic from examination point of view.

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Shivam Chaurasia 6 years, 2 months ago

Yes, most important.

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An infinitely large thin plane sheet has a uniform surface charge density +sigma. Obtain the expression for the amount of work done in bringing a point charge q from infinity to a point, distant r, in front of the charged plane sheet.

Posted by Arjun Ghosh 6 years, 2 months ago

CBSE > Class 12 > Physics

1 answers

? Natasha Yadav? 6 years, 2 months ago

Derivation cannot be explained here, you can refer in your book

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Induced e.m.f is also called back e.m.f?Why?

Posted by Rahul_ Ry(ʘ‿ʘ) 6 years, 2 months ago

CBSE > Class 12 > Physics

1 answers

Sia ? 6 years, 2 months ago

The induced emf is sometimes called 'back emf' because a large current in a coil that is suddenly removed will cause the magnetic field in the coil to collapse and cause a current in the opposite direction.

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What is transformer ?

Posted by Rahul_ Ry(ʘ‿ʘ) 6 years, 2 months ago

CBSE > Class 12 > Physics

4 answers

Jasvinder Atwan 6 years, 2 months ago

Device used to change a.c. voltage

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? Natasha Yadav? 6 years, 2 months ago

No, already completed day before yesterday

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Rahul_ Ry(ʘ‿ʘ) 6 years, 2 months ago

Is your exams are coming ...

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? Natasha Yadav? 6 years, 2 months ago

A transformer is a device that changes voltage from one value to another. Power at the input end is equal to power at output end.

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Difference between a.c. generator and high frequency oscillator

Posted by Anshika Mishra 6 years, 2 months ago

CBSE > Class 12 > Physics

1 answers

Manish Kumar 6 years, 2 months ago

Hi pratima

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Sir how to study physics for cbse class 12 board?

Posted by Tilak Rani 6 years, 2 months ago

CBSE > Class 12 > Physics

1 answers

? Natasha Yadav? 6 years, 2 months ago

Physics is the most interesting subject, but it seems difficult to most of the students because they have already made up their mind about its difficulty. First and foremost , try taking interest in physics, study from the book which seem easier to understand . Understanding and applying is the basic concept to do physics. Coming to numerical, start from easier and then to difficult. Learning and mugging up formulas is temporary, to make formulas remember , practice maximum questions. With practicing you will improve. Solve all NCERT examples and exercises. Always be attentive while attending lecture in your class. In case of doubt regarding any topic ask your teacher and clear it on spot.

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Plz answer me example 4.13 of ncert ch.4 with diagrams

Posted by Surbhi Kumari 6 years, 2 months ago

CBSE > Class 12 > Physics

2 answers

Surbhi Kumari 6 years, 2 months ago

Ok but i have solved this

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? Natasha Yadav? 6 years, 2 months ago

Diagrams are not possible

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What is paramagnetic force

Posted by Jaat Sahil 6 years, 2 months ago

CBSE > Class 12 > Physics

1 answers

Shivam Chaurasia 6 years, 2 months ago

Magnetic force facilliated by paramagneticsubstances when magnetic substance brought near it.. Higher than diamagnetic but lower than ferro

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Methods of generating induced e.m.f .

Posted by Rahul_ Ry(ʘ‿ʘ) 6 years, 2 months ago

CBSE > Class 12 > Physics

2 answers

Rahul_ Ry(ʘ‿ʘ) 6 years, 2 months ago

Nice one...

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Shivam Chaurasia 6 years, 2 months ago

By relative motion of solenoid and magnet.

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How to find emf of a cell

Posted by Sahij Ghumman 6 years, 2 months ago

CBSE > Class 12 > Physics

2 answers

Gursharn Kaur 6 years, 2 months ago

Potentiometer can be used

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Shivam Chaurasia 6 years, 2 months ago

By finding total terninal p.d. across circuit.

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What is magnetic dipole

Posted by Shikha Das 6 years, 2 months ago

CBSE > Class 12 > Physics

2 answers

Sia ? 6 years, 2 months ago

A magnetic dipole is the limit of either a closed loop of electric current or a pair of poles as the size of the source is reduced to zero while keeping the magnetic moment constant.

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Divya Deep Srivastava 6 years, 2 months ago

A magnetic dipole is a pair of equal and opposite poles of same pole stregth separated by a finite distance

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Two identical dipoles each of magnetic moments 1.0Am2 are placed at a separation of 2m with their axis perpendicular to each other. What is magnetic field at mid-way between the dipoles?

Posted by Řøhăň Řąjpůť ✌️✊ 6 years, 2 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

How rainbow is formed in the sky explain

Posted by Akil Sheikh 6 years, 2 months ago

CBSE > Class 12 > Physics

1 answers

Yogita Ingle 6 years, 2 months ago

Rainbow is formed due to the dispersion of sunlight by raindrops suspended in air.

Water drops act like tiny prisms. These water drops refract the sunlight, disperse, then they reflect internally and then refract it again. This is how a rainbow is formed.In the formation of rainbow, when a ray of light falls on water drop, it undergoes refraction and dispersion to form a spectrum. Dispersion takes place inside the water droplets which further reflect internally, refract and then comes out as seven colours.Due to dispersion and internal reflection of light, different colors reach the observer's eye along different paths.

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The mutual inductance between the rectangular loop and the long straight wire as shown in the figure.

Posted by Shalu Kamalia 6 years, 2 months ago

CBSE > Class 12 > Physics

1 answers

Lucky Raj 6 years, 2 months ago

Zero

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Angle of dip.

Posted by Rahul_ Ry(ʘ‿ʘ) 6 years, 2 months ago

CBSE > Class 12 > Physics

5 answers

Rahul_ Ry(ʘ‿ʘ) 6 years, 2 months ago

Nope! At the equator it is 0°.

1Thank You

Divya Deep Srivastava 6 years, 2 months ago

90degree

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Rahul_ Ry(ʘ‿ʘ) 6 years, 2 months ago

?? working hard! Late night studying...

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Rahul_ Ry(ʘ‿ʘ) 6 years, 2 months ago

Thanks but I forgot to write the whole question....that is What is the angle of dip at the equator?

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Aastha Saxena 6 years, 2 months ago

The angle between horizontal component and resultant magnetic field of earth at a place is called angle of dip

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A galvanometer has a coil of resistance 100 Ω showing a full-scale deflection at 50µA . What resistance should be added to use it as (a) a voltmeter of range 50 V (b) an ammeter of range 10mA?

Posted by Ďãřşháñăã Yadav ? ? ? 6 years, 2 months ago

CBSE > Class 12 > Physics

7 answers

Řøhăň Řąjpůť ✌️✊ 6 years, 2 months ago

welcome. ?

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Ďãřşháñăã Yadav ? ? ? 6 years, 2 months ago

thx.

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Řøhăň Řąjpůť ✌️✊ 6 years, 2 months ago

b) 50 μA = (10mA) r /r+100 Ω .... r=0.5 ohm

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Řøhăň Řąjpůť ✌️✊ 6 years, 2 months ago

a) 50 μA = 50v/100 Ω + R ..... solve this u will get R which is equal to 10^6 ohm

1Thank You

Řøhăň Řąjpůť ✌️✊ 6 years, 2 months ago

When a potential difference of 50 V is applied across the voltmeter, full-scale deflection should take place. Thus, 50µA should go through the coil.

1Thank You

Řøhăň Řąjpůť ✌️✊ 6 years, 2 months ago

To convert galvanometer to voltmeter, connect a large resistance in series with it. To convert galvanometer to ammeter, connect a small resistance in parallel with it. The current through the galvanometer should not exceed its full scale current.

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Ďãřşháñăã Yadav ? ? ? 6 years, 2 months ago

it's not much important if ur free then answer otherwise OK

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Difference between lens formula and mirror formula

Posted by Jaat Sahil 6 years, 2 months ago

CBSE > Class 12 > Physics

1 answers

Shivam Chaurasia 6 years, 2 months ago

Mirror formulae gives relation ship between focal length, object distance and image distance for every sphericalmirror or plane.while lens formukae gave relationship for lens. Difference in formula only occur we take u always -

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What is lenzs law

Posted by Md Ashfak Khan 6 years, 2 months ago

CBSE > Class 12 > Physics