A piece of copper and another of germanium are cooled from room temperature to 80 K . The resistance of...

copper decreases and germanium increases

copper increases ∧ germanium decreases

Copper and Silicon are cooled from 300 K to 60 K . The specific resistance

decreases in copper but increases in silicon

increases in copper but decreases in silicon

Constantan wire is used in making standard resistances because its

temperature coefficient of resistance is negligible

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Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 1>Q 103

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A heater coil is cut into two equal parts and only one part is used for heating. The heat generated will now be

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Important Questions on Current Electricity

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Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 1>Q 104

If voltage across a bulb rated

220

Volt-

100

Watt drops by

2.5 %

of its rated value, the percentage of the rated value by which the power would decrease is :

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Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 1>Q 105

The specific resistance of a conductor increases with

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Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 1>Q 106

In the figure, a part of circuit is shown:

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Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 1>Q 107

In the shown circuit, what is the potential difference across $A$ and $B$ .

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Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 1>Q 108

The reading of voltmeter is

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Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 1>Q 109

The drift velocity of electrons in a conducting wire is of the order of $1 mm s^{- 1}$ , yet the bulb glows very quickly after the switch is put on because

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Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 1>Q 110

In a household electric circuit, which of the following is/are correct?
(A) All electric appliances drawing power are joined in parallel.
(B) A switch may be either in series or in parallel with the appliance which it controls.
(C) If a switch is in parallel with an appliance, it will draw power when the switch is in the 'off' position (open).
(D) If a switch is in parallel with an appliance, the fuse will blow (burn out) when the switch is put 'on' closed.

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Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 1>Q 111

Calculate the effective resistance between $A$ and $B$ in the following network.

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