Question

Chapter: Electricity (Class 9)​

Answer 1

$\bf{Question-}$

A stream of electrons with kinetic energy equal to 100 keV p@ss across a cross section of a conductor in 0.5s. If the potential difference between the ends of conductor is 5 V find the number of electrons that p@ss across the conductor in one second. (The charge on an electron is $\sf{1.6\times10^{-19}$).

$\bf{Solution-}$

Given -

• kinetic energy, K.E = 100 keV
• time taken to p@ss across a cross section, t= 0.5 seconds
• potential difference between the ends of conductor, V= 5V

To find -

• the number of electrons that p@ss across the conductor in one second.

Solution -

We know,

               $\:\:\:\:\:\:{\sf{V=\frac{w}{q}}}$

We can also write it as,

               $\:\:\:\:\:\:{\sf{V=\frac{K.E}{q}}}$

We are also know,

                $\sf{q = ne}$

then,

$\implies\sf{5=\frac{100\times10^3\cancel{e}\:V}{n\cancel{e}}}$

$\implies\sf{5n=100\times 10^3}$

$\implies\sf{n=\frac{\cancel{100}^{20}\times10^3}{\cancel{5}_{1}}}$

$\implies\bf{n=2\times10^4}$

Above,

• V = potential difference
• w = work done
• q = quantity of charge
• n = number of electrons

Answer 2

Answer:

Hope it's correct thank you ♡(∩o∩)♡