At what distance from a long straight wire carrying a current of 10 A is the magnetic field equal to the earth's magnetic field of 5 ｘ 10⁻⁵ T? (Answer: 0.04 m) 



Given:

Current =  I =  10 A

Magnetic Field = B = 5 ｘ 10⁻⁵ T

Permeability of free space = µ₀ = 4 ㄫ ｘ 10⁻⁷ H m⁻¹

To Find:

Radial Distance from the wire = r = ?


Solution:

Using Ampere's Law

B = µ₀I2ㄫr

or

r = µ₀I2ㄫB

by putting the corresponding values

r = 4ㄫｘ10⁻⁷Hm⁻¹ｘ10A2ㄫｘ5ｘ10⁻⁵T

r = 40ㄫｘ10⁻⁷Hm⁻¹A10ㄫｘ10⁻⁵T

r = 40ｘ 10⁻³  m

r = 4 ｘ 10⁻² m

or 

 r = 0.04 m ------------------ Ans.



************************************
⭐ Henry 'H' is the unit of measurement for Inductance:

1 H = Wb A⁻¹ =  V s A⁻¹ = kg m² s⁻² A⁻²   [Wb= Weber, A=Ampere, V=Volt]



⭐ Weber 'Wb' is the unit of measurement for Magnetic Flux:

1 Wb =  V s = kg m² s⁻² A⁻¹   = H A




⭐ Tesla 'T' is the unit of measurement for Magnetic Field:

1 T =  N m⁻¹ A⁻¹ = kg m s⁻² A⁻¹   


************************************

Shortcut Links For 


1. Website for School and College Level Physics   
2. Website for School and College Level Mathematics  
3. Website for Single National Curriculum Pakistan - All Subjects Notes 

© 2022-Onwards by Academic Skills and Knowledge (ASK)     

Note:  Write me in the comment box below for any query and also Share this information with your class-fellows and friends.