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

It will become n^2 times. Wire length will become n times and by keeping volume same,its new area will be 1/n times the initial area of cross section... now by applying formula of resistance you will get the answer... Hope it may help you...

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Ďãřşháñăã Yadav ? ? ? 6 years, 2 months ago

thx divya. ?

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Divya Deep Srivastava 6 years, 2 months ago

We get n^2.

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Divya Deep Srivastava 6 years, 2 months ago

R is directly proportional to L/A. Now,we R=L*L/A*l=L^2/volume. Now,we compare initial and final R as follows-R1/R2=L1^2/L2^2,volume got cancelled being equal. R1=initial R R2=Final R L1=initial L L2=final L. L1=L,L2=nL Now putting the value of L1 and L2 in eqation,we get R1/R2= L^2/(nL)^2 So,we get R2=n=2. This is the perfect answer. I hope you will understand this expalnation.

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Ďãřşháñăã Yadav ? ? ? 6 years, 2 months ago

thx once again

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Ďãřşháñăã Yadav ? ? ? 6 years, 2 months ago

format bta do answer ka. ? ? ?

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Ďãřşháñăã Yadav ? ? ? 6 years, 2 months ago

yes

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ANSWER

The frequency of a.c. source is doubled. How do R, XL and Xc get affected?

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

CBSE > Class 12 > Physics

1 answers

Shivam Chaurasia 6 years, 2 months ago

XL become 2 times, XCbecomes half ,hence R is 3/2root z with negative sign.

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ANSWER

How can we increase the sensitivity of potentiometer

Posted by Rudra Singh 6 years, 2 months ago

CBSE > Class 12 > Physics

2 answers

Gursharn Kaur 6 years, 2 months ago

By decreasing the potential gradient By increasing the length of wire By increasing its resistance

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Nehil Bhatnagar 6 years, 2 months ago

By decreasing the potential gradient( by increasing length of wire) .

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ANSWER

Why mass warps spacetime around it ?

Posted by Nilotpal Saikia 6 years, 2 months ago

CBSE > Class 12 > Physics

1 answers

Shivam Chaurasia 6 years, 2 months ago

According to einstein theory of relativity and his eqn on rest mass, velocity. Mass warps spacetime around it.

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ANSWER

What is the unit of current

Posted by Lovkesh Sain 6 years, 2 months ago

CBSE > Class 12 > Physics

5 answers

Aastha Saxena 6 years, 2 months ago

Amperr

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Rajik Hussain 6 years, 2 months ago

Ampere

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Premesh Tyagi 6 years, 2 months ago

Ampere

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Sushant Kumar Yadav 6 years, 2 months ago

Ampere

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Utkarsh Mishra 6 years, 2 months ago

Ampere

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ANSWER

Why equipotential surface is perpendicular to electric field lines

Posted by Premesh Tyagi 6 years, 2 months ago

CBSE > Class 12 > Physics

3 answers

Shivam Chaurasia 6 years, 2 months ago

Because electrostatic force is conservative. So net work done in close loop should be zero. Here thete equals to 90 degree. Otger reason is that inside spgerical shell electric potential is same, so perpendicular. While moving ouside electric potential decreases so it will be curve outside.

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Premesh Tyagi 6 years, 2 months ago

Why ohm law is not aplicable for non ohmic conductor

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Lovkesh Sain 6 years, 2 months ago

this is because there is no potential gradient along any direction parallel to the surface , and so no electric field parallel to the surface. This means that the electric lines of force are always at right angle to the equipotential surface.

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ANSWER

A magnet makes 30 oscillation per minutes in the earth's magnetic field. if magnetic field is double then find the period of oscillation of magnet

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

CBSE > Class 12 > Physics

1 answers

Shivam Chaurasia 6 years, 2 months ago

1 oscillation per second it will done

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ANSWER

What is the physical significane of electric field

Posted by Ziya Ansari 6 years, 2 months ago

CBSE > Class 12 > Physics

1 answers

Shivam Chaurasia 6 years, 2 months ago

Helps in determining electric field strength. Helps in determining electric forces on any specific charges at a given time. Since F=qE. Wherever density of electric field lines will be greater there will be greater magnetic force tgere

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Two circular loops of radii r and 2r have current I and I/2 flowing through them in clockwise and anticlockwise sense respectively. if their equivalent magnetic moments are M1 and M2 respectively state the reaction b/w M1 and M2.

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

CBSE > Class 12 > Physics

2 answers

Ďãřşháñăã Yadav ? ? ? 6 years, 2 months ago

but I am getting my answer in - ve. ?

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Shivam Chaurasia 6 years, 2 months ago

M1/M2=1/2 i.e. m1=m2/2

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ANSWER

How to allot my time to English and physical education....along with PCB...??

Posted by ꧁≪Mämƭå ℭℏ۝ᑌĎℎàℜÿ? 6 years, 2 months ago

CBSE > Class 12 > Physics

6 answers

꧁≪Mämƭå ℭℏ۝ᑌĎℎàℜÿ? 6 years, 2 months ago

Thanks..priya

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Priya Dharshini ? 6 years, 2 months ago

According to me do these subjects on ur week ends or before going to sleep give around 1hr to both subjets that will be more than enough remaining do it during exams... u can score 90+..

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Srishti Choudhary ✍⏳ 6 years, 2 months ago

Hey...unke liye 1hr bhot h....agr dono m jyada pdhne ki need nhi h toh...1 hr to each...of them...enough ....present time ...physics or chemistry k numericals pr...concentrate kr....

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꧁≪Mämƭå ℭℏ۝ᑌĎℎàℜÿ? 6 years, 2 months ago

Good idea...

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Anjaan Ladka 6 years, 2 months ago

Give 1 hour to each of them on sunday Surely your problem will be solved

1Thank You

Anjaan Ladka 6 years, 2 months ago

Sunday is for these subjects

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ANSWER

In addition of charges vector form use to add charges with formula [under root {a2+b2+2abcostheta}]

Posted by Byydhdb Rhdhd 6 years, 2 months ago

CBSE > Class 12 > Physics

1 answers

Shivam Chaurasia 6 years, 2 months ago

Charges are always added algebraically simply not by vector relation since they are scalar

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ANSWER

Why my negative marks happen in coaching phase test

Posted by Gaurav Sharma 6 years, 2 months ago

CBSE > Class 12 > Physics

1 answers

Priya Dharshini 6 years, 2 months ago

Negative marks happens in most of the competitive exams.. it is just for our practice

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ANSWER

Axial point and equitorial point of dipole moment derivation

Posted by Vimlesh Kumar Bind 6 years, 2 months ago

CBSE > Class 12 > Physics

2 answers

Anjaan Ladka 6 years, 2 months ago

Can't tell here

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Gaurav Sharma 6 years, 2 months ago

Axial point = 2p/r^3 and equitorial point= p/r^3

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ANSWER

Axial poit and equitirial point of dipole moment

Posted by Vimlesh Kumar Bind 6 years, 2 months ago

CBSE > Class 12 > Physics

1 answers

S.... ????☺ 6 years, 2 months ago

Axial point is a point on the axis of dipole and equatorial is a point on the normal of an dipole that is formed from the centre

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ANSWER

Axial poit and equitorial point of electric dipole

Posted by Vimlesh Kumar Bind 6 years, 2 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

What does mean by Capacitance btw Capacitor???

Posted by Abhilasha Choudhari 6 years, 2 months ago

CBSE > Class 12 > Physics

4 answers

Premesh Tyagi 6 years, 2 months ago

The ability to store charge is called capacitance and capacitor is used to store charge it consist of two conductor separated by an insulator

2Thank You

Shivam Chaurasia 6 years, 2 months ago

Capacitance is capacity of a capacitor to hold energy. Higher capacitance higher will be holding capacity of a capacitor. Capacitor is a device while capacitance is its property.

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Anjaan Ladka 6 years, 2 months ago

Capacitor is a device which is used to store charge.

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Rishabh Kumar Jha 6 years, 2 months ago

Capacitance is the capacity of capacitor to store charge

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ANSWER

My physics is so week So how i can improve it

Posted by Palak Singh 6 years, 2 months ago

CBSE > Class 12 > Physics

9 answers

Ayush Singh 6 years, 2 months ago

No need to worry about this just buy any refresher and start making notes with the help of it and they have alot of questions so after studying any topic just solve question related to it and practice all deprivation 2-3 times and then u find urself enjoying physics... Good luck

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Priya Dharshini ? 6 years, 2 months ago

Physics is my weak subject also... i give every day 1.5 to physics.. i do everyday around 20 sums and practice formula and derivations once. Same way u could try. Then physics would become ur strong subject

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Gracie Lauren 6 years, 2 months ago

Sorry its not tough ...witing mistske .I'm really sorry .SHREYASI SINGH

2Thank You

Gracie Lauren 6 years, 2 months ago

Only practice with full confidence .bot to take it as boring but take it as interesting

1Thank You

Gracie Lauren 6 years, 2 months ago

First of all never think that it's tough and the other one is try to study it with full confidence and interest and that only makes your physics strong .it's not just a book it's what you are from how where.? Try to create curiosity to know something new..i know thats will be a boring for you but that's teuth.believe me .i always read it with full enjoyment .it's not boring..

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Řøhăň Řąjpůť ✌️✊ 6 years, 2 months ago

?? refresher are those books which have detail content of any topic nd their language are simple so that student can easily catch up the points. few refreshers are SL pradeep, DC payday etc etc. ?

2Thank You

Tanvi Toor 6 years, 2 months ago

@shreyasi refresher means help book like pradeep's

2Thank You

Palak Singh 6 years, 2 months ago

What is refesher i can't understand

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Řøhăň Řąjpůť ✌️✊ 6 years, 2 months ago

physics is all about numerical. practice maximum numerical. nd for numerical ur concept should be clear nd for clearing ur concept u should prefer refresher as if u r weak in physics then I would suggest you to read chapter from refresher not from ncert becoz ncert is for those who understand physics very well as ncert question are not so easy they have their standard. back to point do conceptual question from every topic. make a daily habit of solving at least 25 numerical daily. nd during examination time solve ncert examples as well as back exercise.

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ANSWER

Two insulated copper spheres AAnd B. Have a distance 50cm what is the electorstatic repulsive force .If the charde on earth is 6.5×10-7

Posted by Aryanika Agnihotri 6 years, 2 months ago

CBSE > Class 12 > Physics

3 answers

Anjaan Ladka 6 years, 2 months ago

Earth ka charge spheres me kaise rakh diya. Ye bhi bta do ki ye copy kaise kiya

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Řøhăň Řąjpůť ✌️✊ 6 years, 2 months ago

bhai ye copy paste kese kiya. ? ?

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Gaurav Seth 6 years, 2 months ago

Charge on sphere A, q_A = 6.5 × 10⁻⁷ C
Charge on sphere B, q_B = 6.5 × 10⁻⁷ C
Distance between the spheres, r = 50 cm = 0.5 m Force of repulsion between the two spheres

Therefore, the force between the two spheres is 1.52 × 10⁻²N.

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ANSWER

Apply guass law to show that for a charged spherical shell is as if the entire charge were concentrated at the centre

Posted by Sevti Mahave 6 years, 2 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

Free electrons are in continuous motion in a conductor. Even then no magnetic force acts on the conductor unless a current is passed through it. Why?

Posted by Rohit Kumar 6 years, 2 months ago

CBSE > Class 12 > Physics

3 answers

Shivam Chaurasia 6 years, 2 months ago

Bic net displacement during random motion is zeeo. So net w.done will be zero. So no any force will be effective untill they move with drift velocity.

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Anjaan Ladka 6 years, 2 months ago

Beacuse there is a zig zag random motion of electrons inside a conductor the cancel out each othrer's motion thats why no charge moves inside a conductor. If charge does not move than no magnetic field is produced.But when an external electric field is applied free electrons start drifting in the opposite direction of electric field.That means electrons start performing motion thus producing magnetic field.

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Aditya Dwivedi 6 years, 2 months ago

because the net q=0 in conductor

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ANSWER

How does mobility of electrons in a conductor change if the potential difference applied across the conductor is doubled keeping the length and temperature of the conductor constant

Posted by Shekhar Chakraborty 6 years, 2 months ago

CBSE > Class 12 > Physics