Physics Question (1 Viewer)

[AnandDNA]

In a 60.0 W household florescent tube, 60 Joules of energy are supplied each second to produce an electric current of 0.25 A. Calculate how many couloumbs of electric charge move along the tube in 1 second.

Im not sure if im meant to use the Potential difference formula to find charge. And if so then what is the use of the 0.25A or was that included to trick me.

Or if im meant to find the charge using the potential difference formula and then use the current=charge/time to do something

edit: Also is it possible to have a negative voltage

 

[Aerath]

A coulomb is the amount of electric charge passing through a point every second when a current of one ampere flows through that point, equal to 6.25 x 10⁸.

Wouldn't that mean that in your question, there'd be 0.25 C travelling through? Or am I off the track?

 

[AnandDNA]

so i could've used the current equals charge/time formula to get the answer and disregarded the 60.0 W and 60Joules

 

[Aerath]

Well, I dunno, maybe I'm just thinking too simply. I just looked at the definition of a coulomb.

 

[Aerath]

I believe you can also do the question by using the Voltage = Energy/Charge formula.

Voltage can be calculated by the P = VI formula, where you have 60 = V*0.25, V = 240V. Alternatively, you can just know that the current for a household circuit is 240V.

Energy = 60J

Voltage = Energy/Charge
240 = 60/C
C = ¼ Coulomb

 

[AnandDNA]

whats the P=VI formula I've been introduced to like 10 formulas in the last hr so im sorta braindead at the moment sorry :mad1:

 

[Aerath]

Power = Voltage*Current
P = VI

By substituting in Ohm's Law, V = RI, you'll get:

P = I²R
P = V²/R

 

[AnandDNA]

i didnt know about that. Thanks for your help Aereth

btw is there another way to do it without using the P=VI formula just so when i look in my notes i wont be like 'what the hell' when i see the formula

 

[H4rdc0r3]

wait, I learnt this like recently but amps is like amount of coulomb charge flowing pass in 1 second, so if its 0.25A isn't it just 0.25C per second.

edit: might be red herrings. why would u say 60 joules per second and then say 60W, its the same thing. LOL, if im correct all of Aerath's equations got owned.

 

[Aerath]

wait, I learnt this like recently but amps is like amount of coulomb charge flowing pass in 1 second, so if its 0.25A isn't it just 0.25C per second.

edit: might be red herrings. why would u say 60 joules per second and then say 60W, its the same thing. LOL, if im correct all of Aerath's equations got owned.

In which case, you should've read my first post.

 

[Aplus]

This is the most boring module

 

[Aerath]

Wait til you see Cosmic Engine.

 

[Aerath]

lol....i think 0.25C is the right answer.....i dont think its right to assume the 240v because it doesnt say that its connected to a household supply of electricitiy....

I thought that this meant it was household:

In a 60.0 W household florescent tube....

Either way, it doesn't matter, you can still calculate it to be 240V by using P=VI.

 

[robbo2202]

Q=It
= 0.25x1
=O.25

 

[Aplus]

Wait til you see Cosmic Engine.

I love Space, Astrology, Cosmos, etc.