Question

Anyone able to also give me the working to how they figured it out?​

Answer 1

Lamp 1: 4 Volts, and 0.2 Amps

Lamp 2 : 4 Volts, and 0.2 Amps

Step-by-step explanation:

Considering that the three lamps are equal (they have the same resistance R), we can find the actual resistance of the lamps with the information they provide that the potential difference measured across lamp 3 is 8 volts, using Ohm's Law:

`V = I\,*\,R\\R = (V)/(I)\\R= (8)/(0.4) \\R = 20\,\,\Omega`

We can also estimate the potential difference across the lamps 1 and 2 (which are connected in parallel) using Kirchhoff's loop law, which tells us that the 12 volts provided by the battery should equal the addition of voltage drops in lamp 3 plus the drop in the parallel combination of lamps 1 and 2 (call that X):

12 V = 8 V + X

X = 12 - 8 = 4 V

Now, the current circulating through lamp 1 should be given by Ohm's Law:

`V = I\,*\,R\\I = (V)/(R) \\I = (4)/(20)\\I = 0.2 \,\,Amps`

Notice that lamp 2 is equal to lamp 1 so the current value should be the same: 0.2 Amps