Physics M.C.Q (1 Marks)

When n identical cells, each of emf $' e\ '$ and internal resistance $' r\ '$ are connected to the external resistance $' R\ '$ in series, its called series grouping. In series grouping $e _{ eq }= ne$ and $r _{ eq }= nr$ Therefore, current in the circuit $( l )=\frac{ ne }{( R + nr )}$

A wire bound resistor is an electrical passive component that limits current. Wire$-$bound resistors are made by winding the wires of an alloy like manganin on an insulating base. They are relatively insensitive to temperature.

$\text{R}=\frac{\rho}{\text{A}}=50$


resistance of $'5\ '$ equal parts are same.
$\text{R}'=\frac{\frac{\rho}{5}}{\text{A}}=\frac{50}{5}=10\Omega$
All '5' equal parts connect in parallel,

$\frac{1}{\text{R}_\text{eq}}=\frac{1}{10}+\frac{1}{10}+\frac{1}{10}+\frac{1}{10}+\frac{1}{10}=\frac{5}{10}$
$\text{R}_\text{eq}=2\Omega$

Thermal Energy developed $=\frac{\text{v}_2}{\text{R}}\text{t} ($Because in Parallel, voltage is same$)$

$\frac{\text{Thermal Energy developedin "R"}}{\text{Thermal Energy developedin "2R"}}=\frac{\frac{\text{v}^2}{\text{R}}\text{t}}{\frac{\text{v}^2}{2\text{R}}\text{t}}=2:1$

The $V-I$ graph gives the characteristic of a semiconductor. It exhibits non$-$linear behaviour. After a certain voltage, the current decreases as the voltage increases. Gallium arsenide shows this type of behaviour.

Conductors have low resistivities in the range of $10^{-8} \Omega m$ to $10^{-6} \Omega m$.. Metals are good conductors. Conductors are objects or types of material that allows the flow of charge in one or more directions, and a result, the resistance offered against the flow of charge will be less.

Watt is the $SI$ unit of power.
$\text{Power}=\frac{\text{Work done}}{\text{time}}$.
The $SI$ unit of work done is the same as energy, that is, joule and that of time is seconds. Therefore, one watt is equal to one joule per second.

vd drift velocity $=\frac{1}{2}\Big(\frac{\text{eE}}{\text{m}}\Big)\text{t}$
$\text{K.E}.=\frac{1}{2}\text{mv}^2_\text{d}=\frac{1}{2}\text{m}\Big(\frac{1}{4}\frac{\text{e}^2\text{E}^2\text{t}^2}{\text{m}^2}\Big)$
$\text{K.E}.=\frac{1}{8}\frac{\text{e}^2\text{E}^2\text{t}^2}{\text{m}}$
$\text{p}=\text{K.E}.\propto\frac{1}{\text{m}}$
Mass of electron $<$ mass of metalions.
$K.E.$ of electron $> K.E.$ of metalions.

The quantity of charge passing through any cross$-$section per second is nothing but current flowing in the conductor.
As given, the current is steady current, means current is uniform throughout the cross$-$section. Hence it is independent of Area of cross section.

The rate of flow of electric charge through any cross$-$section of a conductor is known as electric current.

Components connected in series are connected along a single path, so the same current flows through all of the components. The current through each of the components is the same, and the voltage across the circuit is the sum of the voltages across each component. In a series circuit, every device must function for the circuit to be complete. One bulb burning out in a series circuit breaks the circuit. A circuit composed solely of components connected in series is known as a series circuit.
The total resistance of resistors in series is equal to the sum of their individual resistances. Hence, the Equivalent resistance is more than the individual resistances because a sum is taken of all the individual resistances. That is, $R_{\text {total }}=R_1+R_2$. The current is given as $I=I_1=I_2$.
Below is the diagrammatic representation of $2$ resistors $R_1$ and $R_2$ connected in series.