EASY

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The $n$ -side of the depletion layer of a $p - n$ junction

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Important Questions on Current Electricity

MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Resistivity of Various Materials

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

EASY

Physics>Electricity and Magnetism>Current Electricity>Resistivity of Various Materials

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

ρ_{C}, ρ_{T}, ρ_{M}

and

ρ_{A}

respectively. Then :

EASY

Physics>Electricity and Magnetism>Current Electricity>Resistivity of Various Materials

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

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HARD

Physics>Electricity and Magnetism>Current Electricity>Resistivity of Various Materials

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.

EASY

Physics>Electricity and Magnetism>Current Electricity>Resistivity of Various Materials

Wire bound resistors are made by

EASY

Physics>Electricity and Magnetism>Current Electricity>Resistivity of Various Materials

A conductor carries a current of

300 mA

. The number of electrons passing through it in

1

minute are ___ .

EASY

Physics>Electricity and Magnetism>Current Electricity>Resistivity of Various Materials

Electric field and current density have relation

EASY

Physics>Electricity and Magnetism>Current Electricity>Resistivity of Various Materials

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

EASY

Physics>Electricity and Magnetism>Current Electricity>Resistivity of Various Materials

Resistance of a carbon resistor determined from colour codes is (

22000 \pm 5 %

)

Ω

. The colour of the third band must be :

EASY

Physics>Electricity and Magnetism>Current Electricity>Resistivity of Various Materials

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

MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Resistivity of Various Materials

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

EASY

Physics>Electricity and Magnetism>Current Electricity>Resistivity of Various Materials

Two copper wires of length

l

and

2 l

have radii

r

and

2 r

respectively. The ratio of their specific resistances is.

EASY

Physics>Electricity and Magnetism>Current Electricity>Resistivity of Various Materials

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}

)

EASY

Physics>Electricity and Magnetism>Current Electricity>Resistivity of Various Materials

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

HARD

Physics>Electricity and Magnetism>Current Electricity>Resistivity of Various Materials

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,

EASY

Physics>Electricity and Magnetism>Current Electricity>Resistivity of Various Materials

A conducting wire of length $l$ , area of cross-section $A$ and electric resistivity $ρ$ is connected between the terminals of a battery. A potential difference $V$ is developed between its ends, causing an electric current. If the length of the wire of the same material is doubled and the area of cross-section is halved, the resultant current would be___

EASY

Physics>Electricity and Magnetism>Current Electricity>Resistivity of Various Materials

A current through a wire depends on time as