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

the 4 bonding e-s of C are present in 2nd orbit so energy required to take them out(Eg) will be very large. So no. of free e-s for conduction is negligible

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Electric flux definition

Posted by Virender Singh 7 years ago

CBSE > Class 12 > Physics

5 answers

Swati Agarwal 7 years ago

It is the total no. of electric field lines passes through an area normal.

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Harish Jat 7 years ago

Electric flux is over an area in a electric field which represent the total number of electric field lines crossing this area

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Snehashish Datta 7 years ago

Electric flux is the total number of electric field lines passing through a surface perpendicularly or normally.

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Priya Mishra 7 years ago

The number of electric field lines passing through any closed surface area is termed as electric flux.

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Krish Kumar 7 years ago

The total number of electric line of force delivery normal to the surface is called electric flux .

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ANSWER

What is the need of displacement current

Posted by Aayush Sharma 7 years ago

CBSE > Class 12 > Physics

1 answers

Sanskriti S 7 years ago

it explains the inconsistency of ampere circuital law ; maintains the property of continuity along a closed path

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ANSWER

Give one example to illustrate the situation where there is only conduction current but no displacement current

Posted by Pratiksha Tiwari 7 years ago

CBSE > Class 12 > Physics

1 answers

Sanskriti S 7 years ago

in conducting wires, where there the EF is not changing with time

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Why photo diode are used under reverse bias

Posted by Shyama Singh 7 years ago

CBSE > Class 12 > Physics

4 answers

Hanu Saini 7 years ago

Same as above

0Thank You

Pratiksha Tiwari 7 years ago

This reduces the response time because in reverse bias it increases the width of dipletion layer which decreases the junction capacitance

2Thank You

Sanskriti S 7 years ago

well it is ncert solved ex 14.6. it's given in detail

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Sanskriti S 7 years ago

because fractional change due to photo effects on 'minority carrier dominated reverse bias current' is more easily measurable than fractional change in forward bias current.

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Is doppler effect included in the syllabus???

Posted by Muskan Singla 7 years ago

CBSE > Class 12 > Physics

3 answers

Hanu Saini 7 years ago

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Pranhav Muthu 7 years ago

Yes

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Christin Mathew 7 years ago

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ANSWER

Are ncert numericals enough for physics exam?

Posted by Nitish Sharma 7 years ago

CBSE > Class 12 > Physics

3 answers

Dhruv Sinha 7 years ago

Personally id say sl arora is much more compact and easier to understand than the ncert. Unlike ncert topics out of syllabus have been marked and u have a lot of questions to practice. However, the volume of sl arora might give u butterflies in ur stomach, so then go for ncert. I hv studied whole year from sl arora and i feel its way better than the ncert. Hence, id say if u want try solving questions from all in one if u have that. It's not as bulky as sl arora but better than ncert for last min prep

1Thank You

Dhruv Sinha 7 years ago

Not at all, study the SL arora or pradeep to get a better question bank

1Thank You

Sanskriti S 7 years ago

100%?; they are more than enough!!!

2Thank You

ANSWER

Why electron can't be accelerated in a cyclotron?

Posted by Akshay Limbu 7 years ago

CBSE > Class 12 > Physics

4 answers

Harish Jat 7 years ago

Electron can not be accelerated by the cyclotron because the mass of electron is very small and a small mass increase a energy of the electron makes the move with very high speed due to this, the electron go quickly out of step with oscillating electric field

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Sanskriti S 7 years ago

'cause mass of e- is small nd small increase in its energy makes it move with a very high speed, so they go quickly out of step with oscillating E. F

3Thank You

Muskan Singla 7 years ago

Becoz it has very small masss due 2 which it can attain very high speed easily

2Thank You

Dhruv Sinha 7 years ago

Cannot be done so because a lrge increase in their energy increases their velocity to a large extent which throws it out of step with the oscillating field

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ANSWER

Derive an expression for the energy stored in a dipole in uniform electric field

Posted by Neha Pachani 7 years ago

CBSE > Class 12 > Physics

2 answers

Dhruv Sinha 7 years ago

t = p x E t = pEsinΦ dW= tdΦ dW= pEsinΦdΦ W = pE integration (sin Φ)dΦ (limits are from Φ1 to Φ2) W = pE(cos Φ1 - cos Φ2) The work done is stored as potential energy. U = pE(cos Φ1 - cos Φ2) If Φ1 = π/2 and Φ2 = Φ U = pE(cos 90 - cos Φ) U = -pEcosΦ U = -p. E

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Sanskriti S 7 years ago

ncert topic 2.8.3

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ANSWER

Derive an expression for the loss of energy when to conductors at different potential are brought into electrical contact. Account for this energy

Posted by Akshay Limbu 7 years ago

CBSE > Class 12 > Physics

0 answers

ANSWER

Tell me about pnp junction

Posted by Netung Tana 7 years ago

CBSE > Class 12 > Physics

1 answers

Sanskriti S 7 years ago

u mean pnp transistor??

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ANSWER

The flux of the electrostatic field through the closed surface S1 is found to be 4 times that theough closed surface S .find the magnitude of the charge Q given q1=1micro C q2= 2micro C

Posted by Utkarsh Gupta 7 years ago

CBSE > Class 12 > Physics

0 answers

ANSWER

Why short wave band used for long distance radio broadcast??

Posted by Anjali Sharma 7 years ago

CBSE > Class 12 > Physics

2 answers

Akash Joshi 7 years ago

Because we did not use long wave band????

0Thank You

Cicil George 7 years ago

Long distance radio broadcasts use shortwave bands because only these bands can be refracted by the ionosphere

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Derivation of analytical solutions is imp or not???

Posted by Ishita Pandey 7 years ago

CBSE > Class 12 > Physics

0 answers

ANSWER

Obtain the expression for the capacitance of a parallel plate capacitor in vacuum in terms of plate area A and separation d between the plates?

Posted by Gurleen Kaur 7 years ago

CBSE > Class 12 > Physics

1 answers

Nivetha Vijayakumar 7 years ago

€0A/d where €0 is epsilon knot, permitivity in free space.

1Thank You

ANSWER

Explain working of ac generator

Posted by Gujjar Ji 7 years ago

CBSE > Class 12 > Physics

2 answers

Gaytri Devi 7 years ago

It coverts electrical energy to mechinal energy

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Akash Joshi 7 years ago

It needs electricity

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ANSWER

Transistor as an oscillator is imp. for exam??

Posted by Anjali Sharma 7 years ago

CBSE > Class 12 > Physics

1 answers

Shivam Keshri 7 years ago

Nope...it isn't in syllabus

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What are the list of optical instruments in the syllabus???

Posted by Shivam Keshri 7 years ago

CBSE > Class 12 > Physics

1 answers

Sanskriti S 7 years ago

simple nd compound microscope, telescope(refeacting nd reflecting both)

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Hugen principle refraction

Posted by Ay3Kay . 7 years ago

CBSE > Class 12 > Physics

0 answers

ANSWER

lc oscillator ka final result kya h??

Posted by Riya Singhal 7 years ago

CBSE > Class 12 > Physics

2 answers

Deepakshi Dhiman 7 years ago

It converts dc into ac with high frequency

2Thank You

Sanskriti S 7 years ago

The energy in the system oscillates b/w capacitor nd inductor by the natural ang freq., w=1/under root LC

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ANSWER

Two infinite parallel planes have uniform charge density of sigma1 and sigma 2. Determine the electric field to the 1-left of the sheets. 2-between them

Posted by Pranjal Pandey 7 years ago

CBSE > Class 12 > Physics

6 answers

Soumya Dhyani 6 years, 11 months ago

Can someone post the proper solved answer

0Thank You

Soumya Dhyani 6 years, 11 months ago

Are u Sanskriti Saini

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Kartik Periwal 7 years ago

Actually Sanskriti it depends on the sign of sigma

2Thank You

Sanskriti S 7 years ago

yeah Kartik u're correct, bt there is - ve sign also with EF on left as per sign convention

2Thank You

Kartik Periwal 7 years ago

To the left sigma1+sigma2/2€ and in between sigma1-sigma2/2€a

2Thank You

Sanskriti S 7 years ago

sigma 1 & 2 are of same sign or opp.??

2Thank You

ANSWER

How base current controls collector current?

Posted by Sachin Kumar 7 years ago

CBSE > Class 12 > Physics

2 answers

Sanskriti S 7 years ago

also from output characteristic, we can see that ic changes with change in ib

0Thank You

Kartik Periwal 7 years ago

If u increase the base area when the majority carrers move from emitter to base the electron hole recombination process occur and it reduces the majority carriers to move towards collector region and hence the collector current reduces

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I have not prepared any thing help me

Posted by Ajay Charan 7 years ago

CBSE > Class 12 > Physics

0 answers

ANSWER

A telescope resolves but microscope magnifies...justify

Posted by Urvi Nagpal 7 years ago

CBSE > Class 12 > Physics

1 answers

Suhani Rana? 7 years ago

Resolution is the ability to differentiate two very clpsely situated ppint of light whereas magnification is ability to magnify . Now telescope shows us very far off object which are very close to each other with respect to us in distinct and microscope zooms the things . Thus telescope resolve and microscope magnifies

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Which book contain simplest derivations apart from NCERT............HCV or SL Arora

Posted by Shivam Keshri 7 years ago

CBSE > Class 12 > Physics