Shrajesh thapa

If the cross sectional area of potentiometer wire is not uniform , then potential gradient will not be same at all places on the potentiometer wire. Consequently, the measured value of potential difference will not be correct.

Every joint introduces some resistance which is not taken into consideration. This may introduce error in the measurement. Further it is not necessary that the wire has uniform thickness throughout its length

The potential difference per unit length of the wire of a potentiometer is called its potential gradient. Smaller the potential gradient, better its sensitivity.

With increase in length the potentiometer becomes more sensitive. The fall of potential is proportional to the length of the wire only if the wire is of uniform thickness.

The longer is the length of the potentiometer wire, the higher is the accuracy because the potential drop on the wire per unit length decreases as the length of the Wire increases .Hence the potentiometer measures emf more accurately.

Copper wire is not used in potentiometer because of its low resistivity. As a result resistance of the wire will be small and it will difficult to get a null point during the experiment.

When the resistances in the four arms of the bridge are of the same order, the bridge is most sensitive.

The reason for this is that the balance point is obtained at the middle portion of the meter bridge wire which will be more accurate.

Post office box is named as post Office box because the instrument was designed to

measure the resistance the telegraph wire in a post office.

Kirchhoff's first law is based on the principle Of conservation of charge and

is based on the principle of conservation energy.

We should not use Wheatstone bridge for measuring high resistance

because in this case we have to use a galvanometer of high internal

resistance. It will make low current flow through flow through the galvanometer

which will make it less sensitive.

When the circuit contains more than onesourceof emf and the current is

divided into many branches, the circuit will very complicated . Then

we cannot analyze the circuit by using only ohm's law. But in this case

Kirchhoff's laws simplify it to analyze the circuit.

Ohm's law can be used to analyze simple electric circuits only but it

cannot be used to analyze the complicated electric circuits containing

many components and loops. It can be done by using Kirchhoff's

So, Kirchhoff's laws are preferred over ohm's law in an electrical

because Kirchhoff's laws can used to analyze the circuits con

manysources of emf.

A meter bridge is also called a slide wire bridge because the jokey is

slided over the wire of one meter length in the bridge while doing the

experiment.

A slide wire bridge is called meter bridge because in a slide wire, wire of

one meter is used to form Wheatstone bridge and it works on

Wheatstone bridge principle.

The Wheatstone bridge is not suitable for measuring very low resistance because it is based on a ratio of two resistances, and the resolution of the bridge decreases as the ratio approaches 1. This means that the Wheatstone bridge is not accurate enough to measure very small changes in resistance.

Kirchhoff's laws are related to the law of conservation ff Charge and the law of conservation of energy. The first Kfrchhoff's law is based on the law of conservation of charge and the second law in based upon

Of conservation Of energy.

-Yes, we can use Kirchhoff’s laws to both a.c. and d.c. It is because the

Conservation laws of charge and energy are followed by both a-c. and

d.c. Kirchhoff’s first law concludes the conservation of change and the

second law concludes the conservation of energy.