Question: The attraction capacity of electromagnet will increase if the_______________?

• 1. core length increases i
• 2. core area increases
• 3. flux density decreases
• 4. flux density increases

Question: The susceptibility of paramagnetic materials generally lies between____________?

• 1. KT3 and 1CT6
• 2. 1CT3 and 1CT7
• 3. KT4 and KT8
• 4. 10″2 and KT5

Question: Temporary magnets are used in______________?

• 1. loud-speakers
• 2. generators
• 3. motors
• 4. all of the above

Question: For which of the following materials the net magnetic moment should be zero ?

• 1. Diamagnetic materials
• 2. Ferrimagnetic materials
• 3. Antiferromagnetic materials
• 4. Antiferrimagnetic materials

Question: Which of the following statements is correct ?

• 1. The conductivity of ferrites is better than ferromagnetic materials
• 2. The conductivity of ferromagnetic materials is better than ferrites
• 3. The conductivity of ferrites is very high
• 4. The conductivity of ferrites is same as that of ferromagnetic materials

Question: Core of an electromagnet should have____________?

• 1. low coercivity
• 2. high susceptibility
• 3. both of the above
• 4. none of the above

Question: Main causes of noisy solenoid are______________?

• 1. strong tendency of fan out of laminations at the end caused by repulsion among magnetic lines of force
• 2. uneven bearing surface, caused by dirt or uneven wear between moving and stationary parts
• 3. both of above
• 4. none of the above

Question: Magnetism of a magnet can be destroyed by_____________?

• 1. heating
• 2. hammering
• 3. by inductive action of another magnet
• 4. by all above methods

Question: A conductor carries 125 amperes of current under 60° to a magnetic field of 1.1 tesla. The force on the conductor will be nearly______________?

• 1. 50 N
• 2. 120 N
• 3. 240 N
• 4. 480 N

Question: A conductor 2 meters long moves at right angles to a magnetic field of flux density 1 tesla with a velocity of 12.5 m/s. The induced e.m.f. in the conductor will be____________?

• 1. 10 V
• 2. 15 V
• 3. 25V
• 4. 50V