Current Electricity

21. Conductance : mho ::

1. resistance : ohm
2. capacitance : henry
3. inductance : farad
4. lumen : steradian

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22. Conductance is reciprocal of

1. resistance
2. inductance
3. reluctance
4. capacitance

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23. Copper wire of certain length and resistance is drawn out to three times its length without change in volume, the new resistance of wire becomes

1. 1/9 times
2. 3 times
3. 9 times
4. unchanged

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24. Current velocity through a copper conductor is

1. the same as propagation velocity of electric energy
2. independent of current strength
3. of the order of a few ˆ.s/m
4. nearly 3 x 108 m/s

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25. Electric current passing through the circuit produces

1. magnetic effect
2. luminous effect
3. thermal effect
4. chemical effect

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26. Electric pressure is also called

1. resistance
2. power
3. voltage
4. energy

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27. For testing appliances, the wattage of test lamp should be

1. very low
2. low
3. high
4. any value

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28. For which of the following ‘ampere second' could be the unit?

1. Reluctance
2. Charge
3. Power
4. Energy

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29. Four wires of same material, the same cross-sectional area and the same length when connected in parallel give a resistance of 0.25 Q. If the same four wires are connected is series the effective resistance will be

1. 1 Q
2. 2 Q
3. 3 Q
4. 4 Q

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30. Heat in a conductor is produced on the passage of electric current due to

1. reactance
2. capacitance
3. impedance
4. resistance

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