Chapter 11 · Question 8

Why are household electric circuits arranged in parallel rather than in series? Explain the advantages of a parallel arrangement.

Answer Revealed

Direct Answer:

Household circuits use parallel arrangement because: (i) each appliance gets the full supply voltage so it operates at its rated power, (ii) each appliance has its own switch and can be operated independently, (iii) if one appliance fails or is switched off, other appliances continue to work, and (iv) the overall resistance of a parallel circuit is lower, allowing each appliance to draw its required current without affecting others.

Simple Explanation

Your home's electrical wiring is parallel so that every device — your fan, fridge, and phone charger — gets the full 220 V it needs. If they were in series, switching off the fan would also cut power to your fridge. Also, in series each device would get only a fraction of the voltage, so nothing would work properly.

Exam-Ready Structure

Parallel arrangement is preferred over series for household circuits due to several practical advantages: 1. Independent operation: In a parallel circuit, each appliance is connected across the same two points, so each can be switched on or off independently without affecting the working of other appliances. 2. Full rated voltage: Each appliance receives the full supply voltage. This means devices with different power ratings can operate properly. In a series circuit, the voltage would divide, and each appliance would get only a fraction of the supply. 3. Failure isolation: If one appliance develops a fault or is disconnected, the other appliances connected in parallel continue to function normally. In a series circuit, a break anywhere stops current in the entire circuit. 4. Lower overall resistance: The equivalent resistance of a parallel combination is less than the smallest individual resistance. This allows each appliance to draw the current it needs. In a series circuit, the same current would have to pass through every appliance, which is unsuitable for devices with different power requirements. 5. This is why the NCERT chapter treats parallel connection as the useful arrangement for electrical devices that must work independently.

Key Points

Each appliance gets the full supply voltage (220 V) in a parallel arrangement
Appliances can be operated independently — each has its own switch
Fault in one appliance does not affect the working of others
Overall resistance in parallel is low, allowing each appliance to draw needed current
In series circuits, voltage divides and a single break stops all current

Why are household electric circuits arranged in parallel rather than in series? Explain the advantages of a parallel arrangement.