A copper wire of length 10 m and radius m has electrical resistance of 10 . The current density in the wire for an electric field strength of 10 is [2022]

STUDY MATERIALS
COURSES
MORE
SUCCESS STORY
ADMISSION
STORE

Back

JEE ADVANCE

CLASS XI - XII
CRASH COURSE

CLASS XI - XII

CRASH COURSE

JEE MAIN

CLASS XI - XII
CRASH COURSE

CLASS XI - XII

CRASH COURSE

NEET

CLASS XI - XII
CRASH COURSE

CLASS XI - XII

CRASH COURSE

BITSAT

CLASS XI - XII

CLASS XI - XII

CBSE BOARD

CLASS IX

CLASS X

CLASS XI

CLASS XII

CLASS VI

CLASS VII

CLASS VIII

UP BOARD

CLASS IX
CLASS X
CLASS XI
CLASS XII

CLASS IX

CLASS X

CLASS XI

CLASS XII

CUET

CRASH COURSE

CRASH COURSE

Courses

CLASSROOM COURSES
ONLINE COURSES

ONLINE COURSES

More

Solution

Q.
A copper wire of length 10 m and radius $(\frac{10^{- 2}}{\sqrt{π}})$ m has electrical resistance of 10 $Ω$ . The current density in the wire for an electric field strength of 10 $(V/m)$ is [2022]

1 $10^{4} {A/m}^{2}$

2 $10^{6} {A/m}^{2}$

3 $10^{- 5} {A/m}^{2}$

4 $10^{5} {A/m}^{2}$

Ans.
(4)

length, $l = 10$ $m$

radius, $r = \frac{10^{- 2}}{\sqrt{π}}$ $m$

Resistance, $R = 10$ $Ω$

Electric field, $E = 10$ $V/m$

The current density, $j = σ E = \frac{E}{ρ}$ ...(i)

So, $ρ = \frac{R A}{l} = \frac{10 \times π \times \frac{10^{- 4}}{π}}{10} = 10^{- 4}$ $Ω m$

From equation (i), ...(ii)

$V = \frac{10}{10^{- 4}} = 10^{5}$ ${A/m}^{2}$

Want Us to Email you About Special Offers & Updates?