1. The materials are a bit inferior conductors of magnetic flux than air ?

ferromagnetic

paramagnetic

diamagnetic

dielectric

Answer: diamagnetic

Explanation:


2. The magnetic materials exhibit the property of magnetisation because of ?

orbital motion of electrons

spin of electrons

spin of nucleus

all of the above

Answer: all of the above

Explanation:


3. A permanent magnet ?

attracts some substances and repels others

attracts all paramagnetic substances and repels others

attracts only ferromagnetic substances

attracts ferromagnetic substances and repels all others

Answer: attracts some substances and repels others

Explanation:


4. The magneto-motive force is ?

the voltage across the two ends of exciting coil

the flow of an electric current

the sum of all currents embraced by one line of magnetic field

the passage of magnetic field through an exciting coil

Answer: the sum of all currents embraced by one line of magnetic field

Explanation:


5. Materials subjected to rapid reversal of magnetism should have ?

large area of B-H loop

high permeability and low hysteresis loss

high coercivity and high retentivity

high coercivity and low density

Answer: high permeability and low hysteresis loss

Explanation:


6. Which of the following materials are diamagnetic ?

Silver

Copper

Silver and copper

Iron

Answer: Silver and copper

Explanation:


7. The change of cross-sectional area of conductor in magnetic field will affect ?

reluctance of conductor

resistance of conductor

(a) and (b) both in the same way

none of the above

Answer: (a) and (b) both in the same way

Explanation:


8. The working of a meter is based on the use of a permanent magnet. In order to protect the meter functioning from stray magnetic fields ?

meter is surrounded by strong magnetic fields

a soft iron shielding is used

a plastic shielding is provided

a shielding of a non-magnetic material is used

Answer: a soft iron shielding is used

Explanation:


9. A permeable substance is one ?

which is a good conductor

which is a bad conductor

which is a strong magnet

through which the magnetic lines of force can pass very easily

Answer: through which the magnetic lines of force can pass very easily

Explanation:


10. What will be the current passing through the ring shaped air cored coil when number of turns is 800 and ampere turns are 3200 ?

2

4

6

8

Answer: 4

Explanation: