We use alloys for making standard resistors because they have:a)low temperature coefficient of resistivity and high specific resistance.b)high temperature coefficient of resistivity and low specific resistance.c)low temperature coefficient of resistivity and low specific resistance.d)high temperature coefficient of resistivity and high specific resistance.Correct answer is option 'A'. Can you explain this answer?

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Answer

Answer:

Introduction:
In the field of electronics, resistors are essential components used to control the flow of electric current. They are designed to have a specific resistance value, which determines the amount of current flowing through them. Resistors are made from various materials, including alloys, due to their advantageous properties.

Alloys for Making Standard Resistors:
The correct answer to why alloys are used for making standard resistors is option 'A' - low temperature coefficient of resistivity and high specific resistance. Let's understand why this is the case:

Low Temperature Coefficient of Resistivity:
The temperature coefficient of resistivity measures how much the resistance of a material changes with temperature. For standard resistors, it is desirable to have a low temperature coefficient of resistivity because it ensures that the resistance remains relatively constant over a wide range of temperatures.

When the temperature coefficient of resistivity is low, the change in resistance with temperature is minimal. This is important for accurately controlling the flow of current through a circuit, as resistors with stable resistance values provide consistent performance. Alloys, such as constantan and manganin, have low temperature coefficients of resistivity, making them ideal for standard resistors.

High Specific Resistance:
Specific resistance, also known as resistivity, is a measure of how strongly a material opposes the flow of electric current. For standard resistors, it is desirable to have a high specific resistance because it allows for the creation of resistors with higher resistance values.

By using alloys with high specific resistance, resistors with higher resistance values can be manufactured. This is essential in circuits where precise control of current flow is required. Alloys like nichrome and constantan have high specific resistance, making them suitable for standard resistors.

Conclusion:
In conclusion, alloys are used for making standard resistors because they possess a low temperature coefficient of resistivity and high specific resistance. These properties ensure that the resistance of the resistor remains stable over a wide range of temperatures and allows for the creation of resistors with higher resistance values. This is important for accurate and reliable control of current flow in electronic circuits.

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