Physics, asked by mddilshad11ab, 7 months ago

A wire of length 3 m and area of cross-section 1.7 × 10-6 m2 has a resistance 3 × 10-2 ohm.
a. What is the formula for resistivity of the wire and what is the unit of it
b. Calculate the resistivity of the wire​

Answers

Answered by BrainlyPopularman
99

GIVEN :

Length = 3m

• Cross section area = 1.7 ×  \:\: {10}^{ - 6} \:\:

• Resistance = 3 ×  \:\: {10}^{ - 2} \:\:ohm

TO FIND :

(a). What is the formula for resistivity of the wire and what is the unit of it.

(b). Calculate the resistivity of the wire .

SOLUTION :

• We know that –

 \\ \dashrightarrow { \boxed{\bf \: R =   \dfrac{ \rho \: L}{A}}}  \\

• Here –

 \\ \:  \: { \huge{.}} \:  \:  \bf \: R =  resistance \\

 \\ \:  \: { \huge{.}} \:  \:  \bf \: L =  Length \\

 \\ \:  \: { \huge{.}} \:  \:  \bf \: A =  Area \\

 \\ \:  \: { \huge{.}} \:  \:  \bf \:  \rho =  resistivity  \\

• So that –

 \\ \dashrightarrow \large { \boxed{\bf \rho =  \dfrac{RA}{L}}}  \\

Unit = ohm × meter

• Now put the values –

 \\ \implies {\bf \rho =  \dfrac{(3 \times  {10}^{ - 2}) (1.7 \times  {10}^{ - 6})}{ 3}}\\

 \\ \implies {\bf \rho =  \dfrac{ \cancel3  \{1.7 \times  {10}^{( - 6 - 2)}\}}{ \cancel3}}\\

 \\ \implies \large{ \boxed {\bf \rho =  1.7 \times  {10}^{ - 8} \: ohm - m}}\\

 \\ \rule{220}{2} \\


Anonymous: Awesome ✪
mddilshad11ab: Amazing bro
BrainIyMSDhoni: Great :)
amitkumar44481: Great :-)
Anonymous: Perfect :claps:
Answered by Rohit18Bhadauria
86

Given:

Length of wire,l= 3 m

Area of cross-section,A= 1.7 × 10⁻⁶ m²

Resistance of wire,R=  3 × 10⁻²Ω

To Find:

a) What is the formula for resistivity of the wire and what is the unit of it

b) Calculate the resistivity of the wire

Solution:

a) Resistivity ρ of a conductor is given by

\pink{\underline{\boxed{\bf{\rho=\dfrac{RA}{l}}}}}

where,

R is the resistance of conductor

A is area of cross-section of wire

l is length of conductor

Unit of resistivity- Ωm

b) Let the resistivity of wire ρ be

So,

\longrightarrow\rm{\rho=\dfrac{RA}{l}}

\longrightarrow\rm{\rho=\dfrac{3\times10^{-2}\times1.7\times10^{-6}}{3}}

\longrightarrow\rm\green{\rho=1.7\times10^{-8}\ \Omega m}

Hence, the resistivity of given wire is 1.7×10⁻⁸Ωm.


BrainIyMSDhoni: Great :)
mddilshad11ab: perfect
amitkumar44481: Perfect :-)
Anonymous: Nicee!
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