Question

Sushil bought a microwave of 600W and,200V. Calculate the number of electrons passing through it per minute.​

Answer 1

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For a microwave -

Given :-

$\: \: \: \: \: \: \: \: \:$$\sf{power \: (P) = 600 \: W}$

$\sf{potential \: difference \: (V) = 200 \: volt}$

$\: \: \: \:$$\sf{Time \: (t) = 1 \: minute = 60 \: second}$

To Find :-

$\sf{no. \: of \: electrons \: passing \: through \: the \: microwave \: ?}$

Usable Formulas :-

$\sf{Power = potential \: difference\times current}$

$\sf{Charge = current\times Time}$

$\sf{No. \: of \: electrons =\dfrac{Total \: charge}{Charge \: on \: electron}}$

Solution :-

Firstly ,

$\: \: \: \: \: \:$$\sf{P = VI}$

$\: \: \: \: \: \: \:$$\sf{I =\dfrac{P}{V}}$

$\: \: \: \: \: \:$$\sf{I =\dfrac{600}{200}}$

$\: \: \: \: \: \:$$\sf{I = 3 \: ampere}$

Then ,

$\: \: \: \:$$\sf{Q = It}$

$\: \: \: \:$$\sf{Q = 3\times 60}$

$\: \: \: \:$$\sf{Q = 180 \: coloumb}$

Now ,

$\: \: \: \:$$\sf{n =\dfrac{Q}{e}}$

$\: \: \: \:$$\sf{n =\dfrac{180}{1.6\times 10^{-19}}}$

$\: \: \: \:$$\sf{n =\dfrac{180\times 10^{19}}{1.6}}$

$\: \: \: \:$$\sf{n =\dfrac{18\times 10^{20}}{1.6}}$

$\: \: \: \:$$\sf{n =\dfrac{18\times 10^{21}}{16}}$

$\: \: \: \:$$\sf{n = 1.125\times 10^{21} \: electrons}$