Specific resistance of a conductor increases witha)Increase in cross-section and decrease in lengthb)Increase in cross-sectionc)Decrease in cross-sectiond)Increase in temperatureCorrect answer is option 'D'. Can you explain this answer?

Question

Answer

The answer needs formating.. because both a,d,b options are correct as per the formula
R= p×l/a
where p is specific resistance or resistivity.
where Resistance increases with rise in temperature .

Answer

Specific resistance is independent of dimensions and is a property of the material. The property of any material changes with an increase in temperature, thus restivity(specific resistance) is increases with increase in temperature.

Answer

If a conductor is heated,the particles are held free making resistance increase

Answer

Resistance of a conductor is given by R = ρ l/A,
where ρ is the specific resistance, l is the length and A is the cross-sectional area of the conductor.
Now, when l = 1 and A = 1, R = ρ. So specific resistance or resistivity of a material may be defined as the resistance of a specimen of the material having unit length and unit cross-section. Hence, specific resistance is a property of a material and it will increase with the increase of temperature, but will not vary with the dimensions (length, cross section) of the conductor.

Answer

Increase in temperature causes an increase in the specific resistance of a conductor. The specific resistance, also known as resistivity, is a measure of how strongly a material opposes the flow of electric current. It is denoted by the symbol ρ and is measured in ohm-meters (Ω·m).

Explanation:
- The resistance of a conductor is directly proportional to its length and inversely proportional to its cross-sectional area. This can be expressed mathematically as R = ρ * (L/A), where R is the resistance, ρ is the resistivity, L is the length, and A is the cross-sectional area.
- When the cross-sectional area increases, the resistance decreases, as there is more space for the current to flow through. On the other hand, when the cross-sectional area decreases, the resistance increases, as the available space for the current to flow through decreases.
- However, the specific resistance of a material is a property that depends on the material itself, not on the dimensions of the conductor. It represents the inherent resistance of a material to the flow of electric current.
- When the temperature of a conductor increases, the atoms and molecules within the material vibrate more vigorously. This increased thermal agitation disrupts the flow of electrons, leading to a higher resistance.
- The increase in temperature causes an increase in the collision frequency between the electrons and the vibrating atoms or molecules. This results in a greater scattering of electrons, making it more difficult for them to move through the material, and consequently increasing the resistance.
- The effect of temperature on resistivity can be quantified using the temperature coefficient of resistivity (α), which is a material-specific constant. The relationship between resistivity and temperature can be expressed as ρ = ρ0 * (1 + α * ΔT), where ρ0 is the resistivity at a reference temperature, α is the temperature coefficient of resistivity, and ΔT is the change in temperature.
- Different materials have different temperature coefficients of resistivity. For most metals, the resistivity increases with temperature, while for some semiconductors, the resistivity decreases with temperature.
- In conclusion, the specific resistance of a conductor increases with an increase in temperature due to the increased collision frequency and scattering of electrons caused by the thermal agitation of atoms and molecules within the material.

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