Everything Science Grade 11

19.3 CHAPTER 19. ELECTRIC CIRCUITS

Therefore,

R = 2 + 4 = 6 Ω

Step 4 : Apply Ohm’s Law

V = R· I

∴ I =

V

R

=

12

6

= 2 A

Step 5 : Write the final answer

A 2 A current is flowingin the circuit.

Example 5: Ohm’s Law I

QUESTION

Calculate the current (I) in this circuit if the resistors are both ohmic innature.

V =12 V

R 1 =2 Ω

R 2 =4 Ω

I

SOLUTION

Step 1 : Determine what is required

We are required to calculate the current flowingin the circuit.

Step 2 : Determine how to approach the problem

Since the resistors are Ohmic in nature, we canuse Ohm’s Law. There are

however two resistors inthe circuit and we needto find the total resistance.

Step 3 : Find total resistance incircuit

Since the resistors are connected in parallel, thetotal resistance R is:

1

R

=

1

R 1

+

1

R 2