First term / second mid Exam [1433/ 1434] Q12. A conductor of radius I, length and resistivity p has resistance R. What is the new resistance if it is stretched to 4 times its original length?

Respuesta :

Answer:

R' = 4R

Hence, the resistance increases to four times its initial value as well.

Explanation:

The resistance of a conductor in terms of its physical dimensions can be given by the following formula:

[tex]R = \frac{\rho L}{A}\\[/tex]  _______ equation (1)

where,

R = Resistance of the conductor

ρ = resistivity of the material of the conductor

L = Length of the conductor

A = Cross-sectional Area of the conductor

Now, if the length of the conductor is increased to four times, keeping other values constant, then:

[tex]R' = \frac{\rho L'}{A}\\\\R' = \frac{\rho (4L)}{A}\\\\R' = 4\frac{\rho L}{A}[/tex]

using equation (1):

R' = 4R

Hence, the resistance increases to four times its initial value as well.