Electric Current

In hydrogen discharge tube, it is observed that through a given cross-section $5\times {10}^{16}$ electrons are moving from right to left and $5\times {10}^{16}$ protons are moving from left to right per second. The current(in $\mathrm{mA}$) in the discharge tube will be

Current flowing through a wire depends on time as $I=3t^2+2t+5.$ The charge flowing through the cross-section of the wire in time $t=0$ to $t=2 \mathrm{s}$ is 

The amount of charge $Q$ passed in time $t$ through a cross section of a wire is $Q=5t^2+3t+1.$ The value of current at time $t=5s$ is 

The amount of charge $Q$ passed in time $t$ through a cross-section of a wire is $Q=5t^2+3t+1.$ The value of current at time $t=5s$ is _____ in SI unit.

Current is flowing with a current density $J=480 \mathrm{A} \mathrm{c}{\mathrm{m}}^{-2}$ in a copper wire. Assuming that each copper atom contributes one free electron and given that

Avogadro number $=6.0\times {10}^{23}\mathrm{a}\mathrm{t}\mathrm{o}\mathrm{m}\mathrm{s}\mathrm{ }{\mathrm{m}\mathrm{o}\mathrm{l}}^{-1}$

Density of copper $=9.0\mathrm{g}\mathrm{ }{\mathrm{c}\mathrm{m}}^{-3}$

Atomic weight of copper $=64\mathrm{g}\mathrm{ }{\mathrm{m}\mathrm{o}\mathrm{l}}^{-1}$

The drift velocity of electrons is

A current of $2 \mathrm{A}$ is established in a circuit containing an aluminium resistor of length $30 \mathrm{cm}$. If the area of cross-section of the resistor is $0.003 {\mathrm{cm}}^2$ at a point P.The current density at that point will be :

Name the device which is used to measure the voltage in the circuit.

A cylindrical conductor has length $l$ and area of cross-section $A.$ Its conductivity changes with distance $\left(x\right)$ from one of its ends as $\sigma ={\sigma }_0\frac{l}{x}$ [${\sigma }_0$ is a constant]. The electric field inside the conductor as a function of $x$ is $\frac{k}{10} \mathrm{V} {\mathrm{m}}^{-1}$  when a cell of emf $V$ is connected across the ends. Find $k$. [Given that $l=10 \mathrm{m}, x=2 \mathrm{m},\mathit{ }V=10$ Volt.]

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

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

Number of electrons passes through a wire in $2$ minutes is $2.25\times {10}^y$, if current passing through the wire is $300 \mathrm{mA}$. Find the value of $y$.

The current through an element is shown in the figure. Determine the total charge that passes through the element after  $t= 2 \mathrm{s}$ in Coulombs.

In the circuit element given here, if the potential at point $B\text{,} V_{\mathrm{B}}=0\text{,}$ then the potentials of $A$ and $D$ are given as,

Electric _____ between two points in an electric circuit carrying some current is defined as the work done to move a unit charge from one point to the other.

The super conductors are used to levitate trains from the track.

If copper and silicon pieces are heated, the resistance of

What is critical temperature? Explain its importance in superconductors.

What are Superconductors?

At critical temperature, a metal offers _____ resistance to the passage of electricity.

The temperature below which a conductor offers no resistance to the flow of electric current is known as its critical temperature.