LDR Resistance Decreases with Light Intensity

Steps:

• Identify components: Assume circuits use LDRs where resistance falls as light intensity rises, at constant temperature.
• Analyze each circuit: Determine p.d. across measured component based on LDR position in series or divider setups.
• Apply Ohm's law: V = IR; in dividers, V_out = V_in × (R_parallel / total R).
• Compare trends: Check if measured p.d. rises as LDR R drops.

Why D is correct:

• In D, p.d. is across fixed resistor in potential divider with LDR in series arm; as light increases, LDR R decreases, current rises, so V = I × fixed R increases (Ohm's law).

Why the others are wrong:

• A: p.d. across LDR in series; R drops, so V decreases.
• B: p.d. across LDR in parallel; effective R drops, but measured V falls.
• C: Simple series with battery; total V constant, p.d. across LDR decreases.

Final answer: D