Calculate the number of electrons drifting per second through the filament of a 100 W- 220 V bulb , when glowing.(e = 1.6 * 10^ -19 )?

1 Answer
Apr 5, 2018

For a 100 W-220 V bulb to be sustained we must find the current required using the following formula:

#P=VI#

#100=220 times I#
#I=0.4545...# Ampere

Current=(Charge/time)

#I=(Deltaq)/(Deltat)#

(t=seconds)

Plugging in our values:
t=1 second
Hence:
#q=0.4545 C#

1 electron has a charge of #1.6 times 10^-19 C# and we need 0.4545 Coloumb/second to make the lamp glow.

"How many times does #1.6 times 10^-19# fit in 0.4545?"
We use division!

#(0.4545)/(1.6 times 10^-19)=2.84 times 10^18#

So every second, #2.84 times 10^18# electrons drift through the filament.