Current electricity

22. 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

$$ rac{1}{9}$$ times
3 times
9 times
Unchanged

Detailed

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23.7 24.8 41.5 48.3 47.8C117.2 448 288 448 288 448s170.8 0 213.4-11.5c23.5-6.3 42-24.2 48.3-47.8 11.4-42.9 11.4-132.3 11.4-132.3s0-89.4-11.4-132.3zm-317.5 213.5V175.2l142.7 81.2-142.7 81.2z"/> Subscribe on YouTube
SolutionCopper wire of certain length and resistance is drawn out to three times its length without change in volume, the new resistance of wire becomes

across the 60 V power line. If one bulb burns open" class="read-more button" href="https://exam.pscnotes.com/mcq/three-60-w-bulbs-are-in-parallel-across-the-60-v-power-line-if-one-bulb-burns-open/#more-55486">Detailed SolutionThree 60 W bulbs are in parallel across the 60 V power line. If one bulb burns open

26. Which method can be used for absolute measurement of resistances?

Lorentz method
Raleigh method
Ohm's law method
Wheatstone bridge method

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24.8 41.5 48.3 47.8C117.2 448 288 448 288 448s170.8 0 213.4-11.5c23.5-6.3 42-24.2 48.3-47.8 11.4-42.9 11.4-132.3 11.4-132.3s0-89.4-11.4-132.3zm-317.5 213.5V175.2l142.7 81.2-142.7 81.2z"/> Subscribe on YouTube
SolutionWhich method can be used for absolute measurement of resistances?

27. Insulating materials have the function of

Preventing a short circuit between conducting wires
Preventing an open circuit between the voltage source and the load
Conducting very large currents

Detailed SolutionInsulating materials have the function of

28. Bulbs in street lighting are all connected in

Parallel
Series
Series-parallel
End-to-end

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href="https://exam.pscnotes.com/mcq/bulbs-in-street-lighting-are-all-connected-in/#more-55121">Detailed SolutionBulbs in street lighting are all connected in

29. Voltage dependent resistors are used

For inductive circuits
To suppress surges
As heating elements
As current stabilizers

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class="read-more button" href="https://exam.pscnotes.com/mcq/voltage-dependent-resistors-are-used/#more-55094">Detailed SolutionVoltage dependent resistors are used

30. With rise in temperature the resistance of pure metals

Increases
Decreases
First increases and then decreases
Remains constant

Detailed

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11.4 132.3c6.3 23.7 24.8 41.5 48.3 47.8C117.2 448 288 448 288 448s170.8 0 213.4-11.5c23.5-6.3 42-24.2 48.3-47.8 11.4-42.9 11.4-132.3 11.4-132.3s0-89.4-11.4-132.3zm-317.5 213.5V175.2l142.7 81.2-142.7 81.2z"/> Subscribe on YouTube
SolutionWith rise in temperature the resistance of pure metals

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