Question

A glass capillary tube with a diameter of 8.5 mm and length 8 cm is filled with a salt solution with a resistivity of 2.5 ?m. What is the resistance?

Answer 1

Answer:

The resistance is $3.5\times10^{-4}\ \Omega$

Explanation:

Given that,

Diameter of tube = 8.5 mm

Length = 8 cm

Resistivity = 2.5 m

We need to calculate the resistance

The resistance is equal to the product of the resistivity and length divided by the area of cross section .

In mathematical form,

$R = \dfrac{\rho\times l}{A}$

Where, $\rho$=resistivity

l = length

A = area of cross section

Put the value into the formula

$R = \dfrac{2.5\times8\times10^{-2}}{3.14\times(\dfrac{8.5}{2}\times10^{-3})^2}$

$R=3526.32\ \Omega$

$R=3.5\times10^{-4}\ \Omega$

Hence, The resistance is $3.5\times10^{-4}\ \Omega$