Chapter 10 To 10.3

Question 1

What is Kirchhofs second law?
What idea of conservation
What to remember (single…)

Answer 1

That total EMF in to a SINGLE CLOSED LOOP = total VOLTAGE OUT
- this proves conservation of energy

In a Single closed loop

Question 2

On thst note what was Kirchhofs first law again

Answer 2

• total current going into a junction (of a single closed loop) = total current going out
• conservation of charge

Question 3

WHAT HAPPENS TO EMF IF CONNECTED BATTERIES OPPOSITE POLARITIES!!!

Answer 3

Subtract them!

- so if 9 here 6 over way = 3v!

Question 4

How to go about voltage and current in questions ?

Answer 4

• for series it’s one closed loop, so emf = pd and so all the components will take up the emf and it’s shared. Current stays the same
• for parallel each branch forms a new loop so emf = pd of that loop so voltage is same between branches, according to first law current in = out so current splits

Question 5

What to remember about splitting current

Answer 5

Remember go both directions to double check your work, before splitting voltage in parallel see if any was taken by series first = THIS TAKES PRIORITY

Question 6

What happens if you add branches in a parallel circuit to current?

Answer 6

Current increases, as resistance decreases too (more ways to get through)

More branches = more current

Question 7

How to prove resistance is added in series?

Using Kirchhofs laws

Answer 7

K second law = emf in single closed loop = pd out, so all the resistors have add to the emf

• thus V= V1 +V2
• This can be re written as IR= IR1 + IR2
  2) k 1st law says current going into junction = current out, so current is the same everywhere

= R= R1+R2 and they all add up in series!

Question 8

How to show resistance decrease with branch in parallel and derive equation

Answer 8

I= I1+I2

As v is everywhere same we can divide by each side
I/V= I1/V + I2/V
And as I/V = 1/R equation becomes

1/R= 1/R1 + 1/R2