BMAT 2006 Q20 - Physics

Any help?

Hi! These are the rules we apply here:

Parallel circuits rule: Voltage is equal in all branches.
So, the two branches of the given circuit must have the same voltage.

Circuits rule: Resistance in series is always greater than resistance in parallel.

In branch 1 (top branch), the resistors are in series. In branch 2, resistors are in parallel. So we can say that, branch 1 has more resistance than branch 2.

Since current is inversely proportional to resistance (V=IR), branch 1 would have less current than branch 2.

Since voltage is directly proportional to current, voltage in branch 1 would be less than voltage in branch 2.
Hence V1 < V2

Branch 2 splits into two more branches. Hence, voltage splits into two more branches.
V2 = ½V3
R2 has double the voltage of R3. Hence, V2 > V3

Compared to R3, R1 has a higher voltage as there are only 2 resistors in branch 1 whilst there are 3 resistors in branch 2.
V1 > V3

Order: V3 < V1 < V2

Hence, E is the answer. Hope this helps! It’s a little complicated but if you think about the distribution it helps :)) If resistance is higher, voltage is lower.


Thanks so much Raya!