Electricity and Magnetic Fundamentals

181. The magnetic field of a bar magnet most closely resembles the magnetic field of

1. a horseshoe magnet
2. a straight current- carrying wire
3. a stream of electrons moving parallel to one another
4. a current- carrying wire loop

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182. The magnetic field of a magnetized iron bar when strongly heated

1. Becomes weaker
2. Becomes stronger
3. Reverses in direction
4. is unchanged

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183. The magnetic flux of 2000 lines is how many Maxwells?

1. 1000
2. 2OOO
3. 4000
4. 8000

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184. The magnetic flux through a coil changes. This results to the induced emf acting in a direction as to

1. Oppose the change
2. Aid the change
3. Either oppose or aid the change
4. Neither oppose nor aid the change

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185. The magnetic flux through a wire loop in a magnetic field does not depend on

1. The area of the loop
2. The magnitude of the field
3. The shape of the loop
4. The angle between the plane of the loop and the direction

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186. The magnetic materials should have a large hysteresis loss for one of the following applications.

1. Transformers
2. AC motors
3. Permanent Magnets
4. DC generators

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187. The magnetic potential in a magnetic circuit can be measured in terms of

1. Mmf
2. Emf
3. Farad
4. Coulomb

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188. The magnitude of the induced emf in a coil is directly proportional to the rate of change of flux linkages. This is known as

1. Joule's Law
2. Faraday's second law of electromagnetic induction
3. Faraday's first law of electromagnetic induction
4. Coulomb's Law

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189. The mass of proton is _________ the mass of an electron.

1. equal to
2. about 1837 times
3. less than
4. 200 times

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190. The net electrical charge in an isolated system remains constant. This is known as

1. Law of conservation of charge
2. Coulomb's first law
3. Coulomb's second law
4. Law of conservation of energy

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