Internal resistance effect on current and terminal voltage

Steps:

• Total circuit resistance is internal r plus external R; decreasing R reduces total resistance.
• Current I = emf E / (r + R), so I increases as R decreases.
• Terminal p.d. V = E - I r; increasing I raises internal drop I r, lowering V.
• Alternatively, V = E R / (r + R) decreases as R falls, since the fraction R / (r + R) shrinks.

Why B is correct:

• Terminal p.d. V = E - I r shows that higher current amplifies the internal voltage drop, reducing V per Ohm's law.

Why the others are wrong:

• A: Current I increases, does not decrease, as total resistance falls.
• C: Terminal p.d. V decreases due to larger I r drop, does not increase.
• D: Identical to B, but B is the standard correct choice.

Final answer: B