Solution:Concept: When resistors are daisy chained together in a single line and a common current flows through them, they are said to be connected in series.
Individual resistors in a series resistor network add up to give the series combination's equivalent resistance. A series circuit's resistors can be swapped out without affecting the total resistance, current, or power delivered to each resistor or the circuit.
We can calculate the combined resistance by
Req = R1 + R2
⇒Req = 6 + 2
∴Req = 8 ohms
The combined resistance is 8 ohms
Resistors in series carry the same current, but their individual resistance values cause different voltage drops across each resistor, according to Ohm's Law (V = IR) (V = IR)
p.d. applied to two 6 ohm and 2 ohm resistors = 4V
V = IR
⇒I = V/R
⇒I = 4/8
∴I = 0.5A
The current flowing is 0.5A
The potential difference across 6 ohms(r = 6 ohms) can be calculated as,
I = 0.5A
⇒V = IR
⇒V = 0.5×6
∴V = 3V
So, the potential difference across 6 ohms is 3V.
Hence, the answer is option 4.