simple resistor question

[Mark S.]

Hi

I am new to electronics and i just want to get a few things clear in my head.

If i have a simple circuit made up of a 9v battery and a 10 ohm resistor with a power rating 1/4 watt, am i right in saying the resistor would be damaged after a shortish time.

From what i have learned so far

current would be 9v / 10 ohms = 0.9 amps.

0.9 amps * 9 volts = 8.1 watts ,which is too much for the resistor

Have i got this right?

Thanks Mark S.

 

[Dr.EM]

Yep, it will burn up. However, if that is a 9v PP3 type battery, it will not be able to supply 0.9A itself, so the battery would overheat too.

 

[Hero999]

A quicker way of calculating power is V^2/R

 

[RODALCO]

V²/r

Correct !

[alt]+0178 = ²

 

[Hero999]

The alr+0178 thing doesn't work for me, it must be my keyboard driver. By the way R is always a capitol R never lowercase.