Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
Meera shifted to a new house and was fixing light bulbs in her apartment. One of the three bulbs she fixed did not light up. Upon testing she realised it was a case of fused bulb. So, she bought a new one which then lit up perfectly. Select the correct option that describes what happened to the fused bulb.
The switch for the bulb was not turned on
Meera did not fix the bulb to the holder properly
The filament inside it was broken
There was no connection between the bulb holder and the switch
The filament inside it was broken
A bulb functions as a closed electrical circuit where current flows through a thin wire called a filament. If the filament breaks, the circuit becomes an 'open circuit', preventing the flow of electricity, which causes the bulb to stop glowing.
A bulb functions as a closed electrical circuit where current flows through a thin wire called a filament. If the filament breaks, the circuit becomes an 'open circuit', preventing the flow of electricity, which causes the bulb to stop glowing.
Think of a bulb's filament as a bridge across a river; if the bridge collapses (breaks), vehicles (electrons) can no longer reach the other side, and the traffic stops completely.
H=I2Rt тАФ Joule's law of heating representing heat energy produced
V=IR тАФ Ohm's law representing the relationship between potential difference and current
The incandescent bulb operates on the heating effect of electric current. When current I flows through the filament with resistance R, it generates heat according to Joule's Law: H=I2Rt. A broken filament increases the resistance to infinity, breaking the path and resulting in zero current flow, I=0.
A working bulb requires a continuous closed path (closed circuit) for electrons to flow.
The filament is typically made of tungsten due to its very high melting point of approximately 3422┬░C.
Once the filament is broken, the circuit is permanently open, and the bulb is considered 'fused'.
Incandescent filament lighting
Fuses used for circuit protection
Tungsten is used because it glows at high temperatures without melting instantly.
Option A is incorrect because the switch simply controls the closing of the circuit, not the integrity of the filament.
Option B is incorrect because improper installation results in no contact, which is a mechanical issue, not a 'fused bulb' issue.
Option D is incorrect as it describes a wiring fault in the house rather than the failure of the individual bulb component.
C is correct тАФ The filament inside it was broken
In physics exams, always distinguish between a component failure (like a fused bulb) and a circuit failure (like a loose wire or a tripped MCB).
Get instant step-by-step AI explanations, full shift Previous Year Papers (SSC GD, RRB, SSC JE), and regional rank analysis on the official Examoogle App.
Free Download тАв 100K+ Aspirants