Magnetism And Mater

Question 1

Curie weiss law is obeyed by iron at a temperature….

Answer 1

Above curie temperature

Question 2

What is magnetic susceptibility (χ) ?

Answer 2

• denotes the ease with which a material can be magnetised
• χ = I/ H

I: intensity of magnetisation
H: intensity of applied field

Question 3

Intensity of magnetisation

Answer 3

• I= χH
• I = M/ V

M: net dipole moment
V: volume
χ: magnetic susceptibility
H: intensity of applied field

Question 4

Relative permeability (in terms of succeptibility)

Answer 4

μᵣ= 1+ χ

μ: relative permeability of the medium
χ: succeptibility of the medium

Question 5

Magnetic susceptibility of paramagnetic, diamagnetic and ferromagnetic material

Answer 5

• Diamagnetic: small and -ve
• Paramagnetic: small and +ve
• Ferromagnetic: very large and +ve

Question 6

Potential energy of a dipole in magnetic field

Answer 6

• u = -M.B
• u = -MBcosθ

Question 7

Work done in rotating a dipole in uniform magnetic field from θ1 to θ2

Answer 7

W = MB [cosθ1 - cosθ2]

Question 8

Torque in dipole placed in uniform magnetic field

Answer 8

• τ = M × B
• τ =MBsinθ

Question 9

Magnetic dipole moment (M)

Answer 9

M = 2mℓ

• 2ℓ: distance between the poles
• m: pole strength

Question 10

Direction of magnetic dipole

Answer 10

South to north