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If copper and silicon pieces are heated, the resistance of

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Important Questions on Current Electricity

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Physics>Electricity and Magnetism>Current Electricity>Electric Current

The potential difference between points $A$ and $B$ of adjoining figure is

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Physics>Electricity and Magnetism>Current Electricity>Electric Current

Consider four conducing materials copper, tungsten, mercury and aluminum with resistivity

ρ_{C}, ρ_{T}, ρ_{M}

and

ρ_{A}

respectively. Then :

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Physics>Electricity and Magnetism>Current Electricity>Electric Current

Electric field and current density have relation

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Physics>Electricity and Magnetism>Current Electricity>Electric Current

Brown, Red and Orange coloured bands on a Carbon resistor are followed by silver band. The value of resistor is ________.

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Physics>Electricity and Magnetism>Current Electricity>Electric Current

If the valence electrons exactly fill one or more bands, leaving other empty, then the crystal will be

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Physics>Electricity and Magnetism>Current Electricity>Electric Current

A conductor carries a current of

300 mA

. The number of electrons passing through it in

1

minute are ___ .

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Physics>Electricity and Magnetism>Current Electricity>Electric Current

Which of the following acts as a circuit protective device?

HARD

Physics>Electricity and Magnetism>Current Electricity>Electric Current

A steady current

I

is set up in a wire whose cross-sectional area decreases in the direction of the flow of the current. Then, as we examine the narrowing region,

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Physics>Electricity and Magnetism>Current Electricity>Electric Current

Wire bound resistors are made by

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Physics>Electricity and Magnetism>Current Electricity>Electric Current

Resistance of a carbon resistor determined from colour codes is (

22000 \pm 5 %

)

Ω

. The colour of the third band must be :

HARD

Physics>Electricity and Magnetism>Current Electricity>Electric Current

A solar cell is to be fabricated for efficient conversion of solar radiation to emf using material

A .

The solar cell is to be mechanically protected with the help of a coating using material

B .

If the band gap energy of materials

A

and

B

are

E_{A}

and

E_{B}

respectively, then which of the following choices is optimum for better performance of the solar cell.

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Physics>Electricity and Magnetism>Current Electricity>Electric Current

When light shines on a $p - n$ junction diode, the current $I$ versus voltage $V$ is observed as in figure below.

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In which quadrant(s) does the diode generate power, so that it can be used as a solar cell?

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Physics>Electricity and Magnetism>Current Electricity>Electric Current

A circular wire has current density

J = (2 \times 10^{10} \frac{A}{m^{2}}) r^{2}

where

r

is the radial distance, out of the wire radius is

2 mm

. The end-to-end potential applied to the wire is

50 V

. How much energy (in joule) is converted to thermal energy in

100 s

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Physics>Electricity and Magnetism>Current Electricity>Electric Current

The difference between the maximum and minimum values of resistance of a resistor with the color scheme green-green-red-silver is

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Physics>Electricity and Magnetism>Current Electricity>Electric Current

Estimate the magnitude of current that passes through a wire, if

0.1 mol

of electrons flow through it in

40 \min

. (Assume Avogadro number

= 6 \times 10^{23}

)

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Physics>Electricity and Magnetism>Current Electricity>Electric Current

A current through a wire depends on time as

i = α_{0} t + β t^{2}

, where

α_{0} = 20 A s^{- 1}

and

β = 8 A s^{- 2}

. Find the charge crossed through a section of the wire in

15 s .

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Physics>Electricity and Magnetism>Current Electricity>Electric Current

The current in a conductor varies with time

t

I = 2 t + 3 t^{2}

, where

I

is in ampere and

t

in seconds. Electric charge flowing through a section of the conductor during

t = 2 \sec

t = 3 \sec

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Physics>Electricity and Magnetism>Current Electricity>Electric Current

Across a metallic conductor of non-uniform cross section a constant potential difference is applied. The quantity which remains constant along the conductor is:

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Physics>Electricity and Magnetism>Current Electricity>Electric Current

Two copper wires of length

l

and

2 l

have radii

r

and

2 r

respectively. The ratio of their specific resistances is.

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Physics>Electricity and Magnetism>Current Electricity>Electric Current

The

n

-side of the depletion layer of a

p - n

junction

If copper and silicon pieces are heated, the resistance of

Important Questions on Current Electricity

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