Question

What is the advantage of using thick metallic strips to join wires in a potentiometer?

Answer 1

Hint: A potentiometer is a manually adjustable variable resistor with 3 terminals which is used in the measurement of resistance and various other factors of an electrical component. Rotary potentiometers are used on ticket barriers. Potentiometers are very commonly used in controlling electrical devices such as volume controls on audio equipment.

Complete answer:
In a potentiometer, we always use thick metallic strips so as to introduce least resistance while joining the wires. This is also known as contact resistance. Metallic strips have very low resistance and thus can be ignored while measuring the length of the wire which is used to determine null point in potentiometric experiments.
We know that resistance can be expressed as
\[R = \dfrac{{\rho L}}{A}\]
Where \[\rho \] is the resistivity of the given material.
L is the length of the resistor
A is the area of cross-section of the resistor
From this relationship it is clear that as the area of the strip increases the resistance of the strip will decrease.
This would mean that thick metallic strips would decrease the contact resistance and lead to more accurate results.

Note:
Contact resistance can also be reduced by using a four probe method while doing the resistance measurements. In the four-probe case, there is no potential drop across the voltage measurement probe. This leads to reduction in the contact resistance
To accurately measure, the length of thick metallic wire can be measured using centimetre ruling.
Using copper wire will also be a very good option since its resistivity is very low.