Question

Answer this questions

● why the potentiometer supirior than voltmeter ?

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Answer 1

Answer:

To example:

Why Potentiometer is more reliable than Voltmeter ??

Explanation:

If we closely look at the working of a voltmeter, it is actually a Galvanometer attached to a very high resistance. Thus we can see that a huge potential drop occurs at the Voltmeter.

On the other hand, in a Potentiometer , there is no such Potential drops across the Potentiometer wire and hence measures the potential Difference more accurately.

Question 2:

Relationship between J , σ and E

The terms are :

• J => current density
• E => Electric Field
• σ => constant (conductivity)

Now, we say that

J ∝ E

Introducing the constant σ

J = σ × E

Answer 2

QUESTION :-

why the potentiometer supirior than voltmeter ?

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ANSWER:-

$\pink\implies$Potentiometer is a null method device.At null point it does not draw any current from the cell and thus there is no potential drop due to the internal resistance of the cell. ... That is why a potentiometer is preferred over a voltmeter for measuring the emf of a cell.

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QUESTION :-

$\pink\implies$ FIND THE RELATION BETWEEN J AND σ OR E.

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SOLUTION :-

[NOTE:-]

J $\pink\implies$ current density.

E $\pink\implies$ electric field.

σ $\pink\implies$ conductivity.

$\pink\implies$ σ is use as constant.

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.°. J=σ ×E. ( J α E )

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