The coercive force for a certain permanent magnet is `4.0 xx 10^4 A m^(-1)`. This magnet is placed inside a long solenoid of 40 turns/cm and a current is passed in the solenoid to demagnetize it completely. Find the current.
Text Solution
Verified by Experts
The corecivity of `4xx0^(4)Am^(-1)` of the permanent magnet implies that a magnetic intensity `H=4xx10^(4)Am^(-1)` is required to be applied in opposite direction to demagnetise the magnet Here `n(700)/(20cm)=(700)/((20xx10^(-2)m))=3500 "turns/m"` `As " " H=nI` `therefore Current,I=(H)/(n)=(4xx10^(4))/(3500)=11.5A`
Topper's Solved these Questions
MAGNETISM AND MATTER
DC PANDEY ENGLISH|Exercise 5.1|15 Videos
MAGNETISM AND MATTER
DC PANDEY ENGLISH|Exercise 5.2|15 Videos
MAGNETICS
DC PANDEY ENGLISH|Exercise MCQ_TYPE|1 Videos
MODERN PHYSICS
DC PANDEY ENGLISH|Exercise Integer Type Questions|17 Videos
Similar Questions
Explore conceptually related problems
The B-H curve for a ferromagnet is shown in the figure. The ferromagnet is placed inside a long solenoid with 1000 turns/cm. The current that should be passed in the solenoid to demagnetise the ferromagnet completely is :
The coercivity of a small bar magnet is 4xx10^3Am^(-1) . It is inserted inside a solenoid of 500 turns and length 1 m to demagnetize it. The amount of current to be passed through the solenoid will be
An iron rod of volume 10^(-4)m^(3) and relative permeability 1000 is placed inside a long solenoid wound with 5 "turns"//"cm" . If a current of 0.5 A is passed through the solenoid, then the magnetic moment of the rod is
An iron rod of volume 10^(-4)m^(3) and relative permeability 1000 is placed inside a long solenoid wound with 5 turns"/"cm . If a current of 0.5 A is passed through the solenoid, then the magnetic moment of the rod is
The coercivity of a bar magnet is 120A//m . It is to be demagnetised by placing it inside a solenoid of length 120cm and number of turns 72. The current (in A) flowing through the solenoid is:
The coercitivity of a small magnet where the ferromagnet gets demagnetized is 3 xx 10^(3) Am^(-1) . The current required to be passed in a solenoid of length 10 cm and number of turns 100 , so that the magnet gets demagnetized when inside the solenoid , is :
Magnetic lines of force inside a current carrying solenoid are
The magnetic field B inside a long solenoid, carrying a current of 5.00 A, is (3.14 xx 10^-2) T. Find the number of turns per unit length of the solenoid.
A 0.8 m long solenoid has 800 turns and a field density of 2.52xx10^(-3) T at its certre .Find the current in the solenoid
A bar magnet is demagnetized by inserting it inside a solenoid of length 0.2 m, 100 turns, and carrying a current of 5.2 A. The coercivity of the bar magnet is :
DC PANDEY ENGLISH-MAGNETISM AND MATTER-Medical gallery
