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*URGENT* Can anyone help me with question 3b pleaseee??

QUESTION:THE CURRENT IN A SMALL BULB IS 0.20A
A) WHAT IS THE TOTAL ELECTRIC CHARGE WHICH PASSES A POINT IN THE CIRCUIT IN 12min
B) HOW MANY ELECTRONS PASS THIS POINT IN THIS TIME


There is a piece of information at the beginning of the test also saying:
Charge on an electron= 1.6x10 power minus 19
Idk if that will help

PLEASE ALSO EXPLAIN WITH WORKING

1 Answer

5 votes

A) 144 C

The electric current is defined as


I=(q)/(t)

where

q is the charge passing a given point of the circuit in a given time

t is the time interval considered

For this bulb, we know that:

I = 0.20 A is the current


t=12 min \cdot 60 = 720 s is the time considered

Therefore, the amount of charge passing the point in the circuit in this time is


q=It = (0.20)(720)=144 C

B)
9\cdot 10^(20) electrons

The charge of one electron is


e=1.6\cdot 10^(-19)C

And the total charge passing through the point in the circuit in 12 min is


q=144 C

So the total charge can be written as


q=ne

where

n is the number of electrons passing that point of the circuit in 12 min

So, solving for n,


n=(q)/(e)=(144)/(1.6\cdot 10^(-19))=9\cdot 10^(20)

User JRowan
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