Important Questions
1. The horizontal component of earth’s magnetic field at a place is B and the angle of dip is 60°.
What is the value of vertical component of the earth’s magnetic field at equator?
2. What are permanent magnets? Give one example.
3. Which of the following substances are diamagnetic? Bi, Al, Na, Cu, Ca and Ni
4. Which of the following substances are paramagnetic? Bi, Al, Cu, Ca, Pb, Ni
5. The susceptibility of a magnetic material is –2.6 × 10–5. Identify the type of magnetic material and state its two properties.
Sample Questions
1. Show diagrammatically the behavior of magnetic field lines in the presence of
(i) paramagnetic and (ii) diamagnetic substances.
How does one explain this distinguishing feature?
2. Out of the two magnetic materials, ‘A’ has relative permeability slightly greater than unity while ‘B’ has less than unity. Identify the nature of the materials ‘A’ and ‘B’. Will their susceptibilities be positive or negative?
3. Write two properties of a material suitable for making
(a) a permanent magnet, and
(b) an electromagnet.
4. (a) An iron ring of relative permeability μr, has windings of insulated copper wire of n turns per metre. When the current in the windings is I, find the expression for the magnetic field in the ring.
(b) The susceptibility of a magnetic material is 0.9853.Identify the type of magnetic material. Draw the modification of the field pattern on keeping a piece of this material in a uniform magnetic field.
