Question

The circuit shown has an ideal ammeter with zero resistance and four identical resistance light bulbs which are initially illuminated. A person removes the bulb R₄ from its socket thereby permanently breaking the electrical circuit at that point. Which statement is true of the circuit after removing the bulb?

(A) The voltage from B → C increases.

(B) The power supplied by the battery increases

(C) The voltage across R₁ increases.

(D) The ammeter reading is unchanged.

(E) The bulb R₂ maintains the same brightness.

Answer 1

The correct option is: (A) The voltage from B  → C increases.

Explanation:

Breaking the circuit in the lower branch lowers the total current in the circuit, decreasing the voltage across R₁. Looking at the upper loop, this means R₂ now has a larger share of the battery voltage and the voltage across AD is the same as the voltage across BC.