Magnetism and Matter

Q1.The magnetic moment of a bar magnet of pole strength m and length 2l is:

• AM = 2ml
• BM = ml
• CM = m/(2l)
• DM = m/l

Q2.For a good permanent magnet, one needs:

• AHigh retentivity and low coercivity
• BLow retentivity and high coercivity
• CHigh retentivity and high coercivity
• DLow retentivity and low coercivity

Q3.Magnetic susceptibility χ is defined as:

• Aχ = B/H
• Bχ = M/H
• Cχ = M/B
• Dχ = H/M

Q4.The angle of dip at a place is 30°. The ratio of the vertical component to horizontal component of Earth's field is:

• A1/√3
• B√3
• C1
• D2

Q5.The Curie temperature of iron is approximately:

• A273 K
• B500 K
• C1043 K
• D2000 K