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16 Dec 2011 01:02:34 IST

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can value of emf be negative .why?

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can value of emf be negative .why?

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batra

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17 Dec 2011 00:05:16 IST

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no it cannot be -ve because emf is always from positive to negative!!!!!

Prabhjot Singh

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17 Dec 2011 03:02:46 IST

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can value of emf be negative .why?

RAHUL

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22 Dec 2011 13:26:12 IST

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@ Krithika & singh.......................... Before answering this question........... What is the REAL MEANING OF -VE & +VE.......??

ARE THEY EXIST IN THE REAL WORLD........?..........NO..............................

................. MATHEMATICS IS 100% IMAGINARY...........DOES '1'...EXIST.......?....in the case of '2'.......?............the entire mathematics is combination of symbols created by humans for analysing science............................................................................................

MATHEMATICS IS JUST A LANGUAGE................IT IS NOT SCIENCE............BECAUSE SCIENCE IS REAL.......AND MATHEMATICS IS 100% IMAGINARY............LIKE........ENGLISH, HINDI..................ect...........

RAHUL

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22 Dec 2011 13:57:13 IST

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hi..kids,

e.m.f. = voltage or potential difference (not exactly....)........

Electric potential at any point is defined as work done to move a + ve charge from infinity to that point.........

.if Electric field present at that point is +ve ............then we need to PUSH the +ve chage from infinity..........So FORCE &

displacement are in same direction.........so potential is +ve............ Other wise ....if -ve charge is present at that point ........then we need to PULL .......the +ve charge to infinity........... so the potential is -ve..........

potential difference is the difference in electric potential at 2 points........................ consider a battery........it has a

positive terminal & -ve terminal...... if +5V and -5V are the terminals............then............what is its e.m.f................

+ 5V- (-5V)= 10V........... OR .........-5V -(+5V)= -10V..................BUT WE TAKE +VE ANSWER.........

Rabindra Kumar ! A Name of Success !

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30 Dec 2011 17:31:21 IST

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If we consider the opposite in any circuit then we consider negative emf. . e.g. Back emf in motor. .

Mohit Mishra

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1 Jan 2012 22:34:31 IST

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can value of emf be negative .why

Mohit Mishra

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1 Jan 2012 22:46:45 IST

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emf can be negative, but to say emf as negative is incorrect!

sounds confusing??? but i can explain that! suppose we have a battery in which current flows from A to B ie A is +ve terminal and B is -ve terminal. As we know that if current is flowing in it then emf must be positive because negative emf can't make the current to flow!

now if one says that the emf is negative then it simply means that the polarity of the battery is reversed. This means that current now flows from B to A ie B is now +ve terminal and A is now -ve terminal!

any questions regarding this answer shall be cleared

sidharthsekharsahoo

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10 Jan 2012 13:28:08 IST

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yes,its possible ,while charging a battery is emf is -ve

Bipin Dubey

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22 Jan 2012 22:43:22 IST

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I agree with rahul. - or + sign is to show the polarity. Induced emf is -ve as it opposes the reason causing it.

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