Power dissipation depends on current through identical resistors

Steps:

• Power in a resistor is P = I²R; since all R are equal, highest P occurs in branch with highest I.
• Analyze circuit configuration from diagram to find equivalent resistances and currents in branches PQ, QR, RS, SP.
• Use Kirchhoff's laws or simplify series-parallel combinations to calculate I for each branch.
• Compare I values: SP has the largest current.

Why D is correct:

• Branch SP carries the maximum current, so by P = I²R, it dissipates the most power.

Why the others are wrong:

• A: PQ has lower current due to parallel paths diverting flow.
• B: QR shares current with adjacent branches, reducing its I.
• C: RS is in a configuration with higher effective resistance, lowering I.

Final answer: D