Electricity and Magnetic Fundamentals

161. The flux density in an air-cored coil is 10∧-3 Wb/m∧2. With a cast iron core of relative permeability 100 inserted, the flux density will become

1. 10∧-3 Wb/m∧2
2. 10∧-2 Wb/m∧2
3. 10∧3 Wb/m∧2
4. O.1 Wb/mA2

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162. The force acting on a pole of 5 Wb is 25 N. What is the intensity of the magnetic field?

1. 5 N/Wb
2. 25 N/Wb
3. 125 N/Wb
4. 0.2 N/Wb

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163. The force acting on a unit n- pole placed at that point is called

1. Magnetic field intensity
2. Electric field intensity
3. Electromagnetic field intensity
4. Intensity magnetization

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164. The force between two charges placed a given distance apart _________ as the relative permittivity of the medium is increased.

1. increases
2. decreases
3. remains unchanged
4. becomes infinite

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165. The force between two magnetic poles is _________ the relative permeability of the medium.

1. directly proportional to
2. independent of
3. inversely proportional to
4. equal to

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166. The force between two magnetic poles is _________ their pole strengths.

1. directly proportional to
2. the sum of
3. inversely proportional to
4. the product of

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167. The force between two magnetic poles is _________ their poles strength.

1. equal to
2. directly proportional to
3. inversely proportional to
4. directly proportional to the square root of

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168. The force between two magnetic poles varies with the distance between them. The variation is _________ to the square of that distance.

1. Equal
2. Greater than
3. Directly proportional
4. Inversely proportional

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169. The force of attraction or repulsion between two magnetic poles is directly proportional to their strengths.

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

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170. The force of attraction or repulsion between two magnetic poles is inversely proportional to the square of the distance between them. This is known as

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

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