$\huge \sf \color{blue}{\underline{Current~Electricity}}$

Question

abhisar · Answer

`The net flow of charge in a direction through a conducting wire constitutes an electric current.`

abhisar · Answer

$\huge \sf Current~Carriers$
`The charged particles whose flow in a definite direction constitutes the electric current are called current carriers`

Current carriers can either be negatively charged particles or positively charged particles.

$\large \sf \text{(a) Current carriers in solid conductors}$
In solid conductors like metals, the valence electrons are free to move throughout the volume of the metal. Under the effect of an electric field, these valence electrons move in a definite direction and thus cause electric current. `The valence electrons are the current carriers in solid conductors like metal.`

$\large \sf \text{(b) Current carriers in liquids}$
In an electrolyte like $\sf CuSO_4, NaCl$ etc., there are both positively charged ions and negatively charged ions like $\sf Cu^{++}, SO^{--}_4, Na^+, Cl^-$ etc. In a n external electric field both these charges cause electric current. `Thus in liquids both positively and negatively charged ions act as current carriers.`

$\large \sf \text{(c) Current carriers in gases}$
Generally, the gases are bad conductors of electricity but they can be ionized by applying a high potential difference at low pressure or by their exposure to X rays etc. The ionized gas contains both positive ions and electrons. `Thus , both positive ions and electrons are current carriers in gases.`

abhisar · Answer

$\huge \sf Electromotive~Force~[EMF]$
Elctric current is possible in a closed circuit if there is a source of external force (basically a source of energy) which compels the current carriers to move in a definite direction `(i.e from lower potential energy to higher potential energy).` This external force is called as electromotive force or simply emf.

$\large \sf EMF~of~cell$
`It is defined as the maximum potential difference between the two electrodes of the cell when no current is drawn from the cell or cell is in open circuit.`

Suppose in an electrolytic cell there are two electrodes P and N.When the electrodes are immersed in electrolyte, they exchange charges with the electrolyte due to difference in concentration of free electrons in them and electrolyte. If P is anode and N is cathode then p acquires positive potential $\sf v_+$ w.r.t electrolyte and N acquires negative potential $\sf -v_-$ w.r.t electrolyte. Then according to the definition,

$\large \sf \epsilon = v_+-(-v_-)\ \therefore ~~~~~~~~~~~~~~~~~~~~~~~~~~\huge \boxed{\epsilon=v_++v_-}$

abhisar · Answer

$\huge \sf Electric~Current$
`The rate of flow of charge through any cross-section of a conductor is the measure of current.`

$\large \sf \boxed{Electric~current(I)=\frac{Total~charge~flown}{time~taken}=\frac{Q}{t}=\frac{ne}{t}}\~\Here,~Q=net~charge~flown=q_++(-q_-)\t=time~taken\n=number~of~electrons\e=charge~on~electron$

It should be noted that equation $\large \sf I=\frac{ne}{t}$ is applicable for solid conductors.

$\large \sf Unit~of~current$
`SI unit of current is ampere and it is defined as the current which flows when 1C of charge is flowing per second through a conductor.`

$\huge \sf \boxed{1~ampere (A)=\frac{1~coloumb(C)}{1~seond(s)}}$

anonymous · Answer

Ah yes, current electricity brings back memories, this was very well done, thank you so much for making this @Abhisar