Question

Rajat, Sarath and Komal decided to measure resistance of aluminium and took bars of aluminium separately and measured its resistance in same room but got different values of resistance, of same material aluminium. What can be the probable reasons for these variations in resistance for same material?

• A. they took bars of same length but different cross section area
• B. they took bars of same cross section area but different length.
• C. both length and cross section area of bars were different
• D. All of the above

Answer 1

The correct option is D All of the above

The equation representing the dependency of the resistance (R) of a conductor (e.g., a wire) upon the variables that affect it is
$R=p\frac{L}{A}$
where L represents the length of the wire (in meters), A represents the cross-sectional area of the wire $\left(inmeter{s}^2\right)$, and (p) represents the resistivity of the material (in ohm•meter
Basically if the material is same means resistivity (p) is same for both rods, other factors which influence the values of resistance is length and cross sectional area.
Therefore all the above.