Quick Physics/Electronics question rep+

Just trying to help my friend with some physics/electronics coursework and this question kind of made by brain go cold:

The current through a resistor is 17mA. What charge will flow through it in 10 minutes?

Reply 1

Tobedotty

7

charge im assuming mean mAh so its

(1/6)\times17

which equals

2.83333...

?

Reply 2

Entangled

12

Q = It
Q = 17m * (10*60)
Q = 17*600/1000
Q = 10.2C

Reply 3

MC REN

14

yer, charge = current * time

(though i've never seen mAh as units they are clearly valid, and quite suitable here magnitude-wise)

Reply 4

i.am.lost

18

argh flashback to electronics exam :eek3:

Reply 5

Entangled

12

MC REN

(though i've never seen mAh as units they are clearly valid, and quite suitable here magnitude-wise)

It's not good convention to put anything except the kilowatt-hour in terms of hours. Everything (barring kWh) should be written in seconds wherever possible - that is to say in 's'. No 'secs' in physics, as the old one says.

Reply 6

MC REN

14

Entangled

It's not good convention to put anything except the kilowatt-hour in terms of hours. Everything (barring kWh) should be written in seconds wherever possible - that is to say in 's'. No 'secs' in physics, as the old one says.

Yer but in practice most fields have their own conventions for which units they use - which very often aren't the SI ones, and mAh are in fact used quite extensively in describing batteries for example

Reply 7

Entangled

12

MC REN

Yer but in practice most fields have their own conventions for which units they use - which very often aren't the SI ones, and mAh are in fact used quite extensively in describing batteries for example

This is coursework, not industry. :p:

Reply 8

Mehh

8

One will quickly learn that in science the SI is not the be or and end all, far from it in fact.
One usually uses the units that is most convenient for the job. When making comparisons, CGS has its advantages.
However mAh as a unit has a handy magnitude, as a Colomb is a damned insanely large charge.