Seema has two bulbs, one of them is faulty. She connects both the bulbs in parallel land, not in series. Which of the following is NOT the correct reason to do this?
In parallel connection, both bulbs get exactly half amount of voltage in the battery.
Bulbs in Parallel Connection: Understanding the Circuit
Seema chose to connect her two bulbs in parallel, even with one being faulty. This is a common practice in electrical wiring, especially for household appliances. The question asks us to identify the statement that is NOT a correct reason for connecting bulbs in parallel.
Understanding Parallel and Series Connections for Bulbs
To understand why Seema opted for a parallel connection, let's first clarify the fundamental differences between series and parallel circuits, especially when dealing with multiple bulbs.
| Feature | Series Connection | Parallel Connection |
|---|---|---|
| Current Flow | Current is the same through all components. If one component breaks, the circuit breaks, and current stops everywhere. | Current divides among branches. If one branch breaks, current can still flow through other branches. |
| Voltage Distribution | Voltage divides across components. Each component receives a fraction of the total voltage. | Voltage is the same across all parallel branches, equal to the source voltage. |
| Effect of Faulty Bulb | If one bulb is faulty (e.g., filament breaks), the entire circuit becomes open, and all other bulbs go out. | If one bulb is faulty, the other bulbs continue to glow because they are on separate branches and still receive the full voltage. |
| Independent Operation | Components cannot be operated independently; turning one off affects all others. | Components can be operated independently (e.g., with separate switches). |
Analyzing Reasons for Parallel Bulbs Connection
Now, let's examine each given reason in the context of Seema connecting her bulbs in parallel and identify which one is NOT a correct justification for her choice.
- Reason 1: In series, if there is a fault in one bulb, then the whole circuit will be affected.
This statement is true. As explained in the table, in a series circuit, if one bulb fails, it acts as an open switch, breaking the entire circuit. This is precisely why parallel connections are preferred for household wiring or when a faulty bulb is present, as it prevents the entire system from shutting down. So, this is a correct reason to avoid series connection and thus connect in parallel.
- Reason 2: In parallel connection, both bulbs get exactly half amount of voltage in the battery.
This statement is false. In a parallel circuit, all components connected in parallel receive the full voltage of the power source (battery). For example, if the battery provides \(V\) volts, then each bulb connected in parallel across the battery terminals will also have \(V\) volts across it. The voltage does not divide in parallel branches; it remains the same across them. Therefore, this is NOT a correct reason for connecting bulbs in parallel. This statement describes an incorrect characteristic of parallel circuits.
- Reason 3: If there is a fault in one bulb, it can be removed or repaired. Thus, the whole circuit will not be affected.
This statement is true. This is a major advantage of parallel connections. If one of Seema's bulbs is faulty, it can be easily removed or replaced without interrupting the power supply to the other functional bulb or other parts of the circuit. The other bulb will continue to glow normally. So, this is a correct reason to connect in parallel.
- Reason 4: We can operate two bulbs separately in parallel connection.
This statement is true. In a parallel circuit, each branch (and thus each bulb) can be controlled independently, typically by having a separate switch for each. This allows Seema to turn one bulb on or off without affecting the operation of the other bulb. This provides operational flexibility. So, this is a correct reason to connect in parallel.
Conclusion: Identifying the Incorrect Reason for Parallel Connection
Based on our analysis of the characteristics of parallel circuits, the statement that is NOT a correct reason for connecting bulbs in parallel is the one that incorrectly describes voltage distribution.
The correct characteristic of a parallel circuit is that all components across parallel branches receive the same voltage, which is equal to the source voltage. The statement that "In parallel connection, both bulbs get exactly half amount of voltage in the battery" is incorrect because voltage does not halve in parallel; rather, it remains constant across parallel branches.
Important Questions from Network Elements
The maximum safe working voltage for a series combination of two capacitors of rating 2 μF/10V and 4 μF/20V is
- The capacitance 'C' is a measure of the capacitor's potential to store energy in:
Capacitor having lowest capacitance has medium of dielectric :
The inductor is a two-terminal energy storage device whose voltage is proportional to the:
When a capacitor is connected across a battery for a long time it becomes :
