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The electric current through a wire varies with time as $I = I_{0} + β t$ , where $I_{0} = 20 A$ and $β = 3 A s^{- 1}$ . The amount of electric charge crossed through a section of the wire in $20 s$ is:

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Important Questions on Current Electricity

EASY

Physics>Electricity and Magnetism>Current Electricity>Electric Current

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___

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,

EASY

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 .

MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Electric Current

The charge flowing in a conductor changes with time as

Q (t) = α t - β t^{2} + γ t^{3}

, where

α, β

and

γ

are constants. Minimum value of current is:

EASY

Physics>Electricity and Magnetism>Current Electricity>Electric Current

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

Question Image

MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Electric Current

A current of

5 A

is passing through a non-linear magnesium wire of cross-section

0.04 m^{2}

. At every point the direction of current density is at an angle of

60 °

with the unit vector of area of cross-section.
The magnitude of electric field at every point of the conductor is: (resistivity of magnesium

ρ = 44 \times 10^{- 8} Ωm

)

EASY

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

MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Electric Current

The current flowing in a copper voltmeter is

1.6 A

. The number of

{C u}^{+ +}

ions deposited at the cathode per minute is

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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 ___ .

MEDIUM

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

EASY

Physics>Electricity and Magnetism>Current Electricity>Electric Current

The current density in a cylindrical wire of radius

4 mm

4 \times 10^{6} A m^{- 2}

. The current through the outer portion of the wire between radial distances

\frac{R}{2}

and

R

is _____

π A

EASY

Physics>Electricity and Magnetism>Current Electricity>Electric Current

Which of the following acts as a circuit protective device?

EASY

Physics>Electricity and Magnetism>Current Electricity>Electric Current

The current density in a cylindrical wire of radius

r = 4.0 mm

1.0 \times 10^{6} A^{2} m^{2}

. The current through the outer portion of the wire between radial distances

\frac{r}{2}

and

r

x π A

; where

x

EASY

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}

)

EASY

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

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>Electric Current

Ten thousand alpha particles are passing per minute through a straight tube of radius

r

. The resulting electric current is approximately:

EASY

Physics>Electricity and Magnetism>Current Electricity>Electric Current

Constant current is flowing through a linear conductor of non-uniform area of cross-section. The charge flowing per second through the area of conductor at any cross-section is

MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Electric Current

When an electrical appliance is switched on, it responds almost immediately, because

EASY

Physics>Electricity and Magnetism>Current Electricity>Electric Current

The electron in a hydrogen atom circles around the proton in

1.5941 \times 10^{- 18} s

. The equivalent current due to motion of the electrons is

The electric current through a wire varies with time as I=I0+βt, where I0=20 A and β=3 A s-1. The amount of electric charge crossed through a section of the wire in 20 s is:

Important Questions on Current Electricity

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The electric current through a wire varies with time as $I = I_{0} + β t$ , where $I_{0} = 20 A$ and $β = 3 A s^{- 1}$ . The amount of electric charge crossed through a section of the wire in $20 s$ is: