Question

What is effective resistance of three resistors 2 oms 3 oms 4 oms connected in series?

Answer 1

The formula of resistance ...r1 +r2+r3.... 2+3+4=9ohm.....

Answer 2

Series, tot ’em up. You get 2+3+4 which is 9 ohms. Nice ’n’ easy.

Parallel is a bit harder.

You have to tot up the reciprocals first. You do (1/2)+(1/3)+(1/4) and when you do you get 1.08 and loads of threes stretching into the distance. Then you take the reciprocal of that:

1/1.08333333…………..

to get the resistance and doing that you get 0.923 ohms. Not so easy as sometimes you forget that last bit. Never forget the last bit. It loses you marks in exams and looks embarassing when you blow things up.