First slide

Ohm's law

Question

Length of a hollow tube is 5 m, its outer diameter is 10 cm and thickness of its wall is 5 mm. If resistivity of the material of the tube is $1 .7 \times 10^{- 8} Ωm$ then resistance of tube will be

Moderate

A

$5.6 \times 10^{- 5} Ω$
B

$2 \times 10^{- 5} Ω$
C

$4 \times 10^{- 5} Ω$
D

None of these

Solution

$\begin{array}{l} By using R = ρ . \frac{l}{A}; here A = π (r_{2}^{2} - r_{1}^{2}) \\ Outer radius r_{2} = 5 cm \\ Inner radius r_{1} = 5 - 0 .5 = 4 .5 cm \end{array}$
$\begin{array}{l} So R = 1 .7 \times 10^{- 8} \times \frac{5}{π \{{(5 \times 10^{- 2})}^{2} - {(4 .5 \times 10^{- 2})}^{2}\}} \\ = 5 .6 \times 10^{- 5} Ω \end{array}$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App