It is preferable to connect bulbs in series or in parallel?

Question

Examoogle · Accepted Answer

Parallel

Explanation: It is preferable to connect bulbs in parallel because it ensures each bulb receives the full rated supply voltage, independent of other bulbs in the circuit. In a parallel circuit, if one bulb fails, the remaining bulbs continue to operate as the continuity of the other branches remains unaffected.

Working Principle: In a parallel configuration, the potential difference across each branch is identical to the source voltage ($V_{parallel} = V_1 = V_2 = V_n$). Since bulbs are rated for specific voltages, parallel connection allows each to draw its design current ($I = P/V$). Conversely, in series, the voltage divides among the components, causing each bulb to glow dimmer than its rated capacity, and a single open-circuit failure disconnects the entire network.

Key Formulas: $V_{total} = V_1 = V_2 = V_n$ — Voltage in parallel; $I_{total} = I_1 + I_2 + I_n$ — Total current in parallel

Key Points: Constant voltage across all bulbs ensures uniform brightness.; Individual control is possible with separate switches.; Total circuit resistance decreases as more bulbs are added in parallel: $\frac{1}{R_{eq}} = \frac{1}{R_1} + \frac{1}{R_2} + ...$; A fault in one branch does not affect the operation of others.

Advantages: Each bulb receives full rated voltage.; Independent operation of each component.; Easy addition or removal of units without affecting others.

Disadvantages: Requires more wiring compared to series connections.; Total current consumption increases with each additional load.

Applications: Domestic wiring (lighting and appliances).; Commercial electrical distribution systems.

Additional Info: In series circuits, bulbs share the supply voltage, leading to a significant drop in power $P = V^2/R$ and dimming.. Option A is incorrect because it is rarely used for domestic lighting due to the dependency of load performance on other loads in the chain.

Answer: B is correct — Parallel circuits ensure that each bulb receives the full operating voltage and functions independently of other circuit elements.

Exam Tip: Remember: For power distribution, think 'Constant Voltage' (Parallel); for protection, think 'Current Limiting' (Series, e.g., Fuses).

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