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प्रश्न
Why does the filament of an electric bulb in an electric circuit get white-hot, but not the connecting wires?
उत्तर
The filament of an electric bulb is made up of tungsten having high resistance. Due to its high resistance, on passing an electric current through it, electrical energy changes into heat energy. So much heat is produced that filament of bulb becomes white-hot and gives light.
The resistance of connecting wires is very low and hence the connecting wires do not get heated.
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संबंधित प्रश्न
Write symbol and state function of following component in an electric circuit :
cell
State whether the resistance of filament of a bulb will decrease, remain unchanged or increase when it glows.
Name the physical quantity of which the unit is volt
Name the physical quantity of which the unit is coulomb
What do you understand by the term electric current?
The following figure shows a metal rod PQ mounted on an insulated stand. The cap of an uncharged electroscope touches one end Q of the metal rod. A negatively charged ebonite rod is brought near the other end P of the metal rod.
(a) What charge does the end P have?
(b) What charge does the end Q have?
(c) What charge does the cap of the electroscope have?
(d) What charge does the gold leaf have?
(e) Will the leaf diverge or collapse? Give reason.
(f) If the electroscope is now earthed, what charge does the metal rod have?
What is the function of a switch in an electric circuit?
Compare the brightness of two 60 watt bulbs.
When they are connected in parallel.
Explain giving scientific reasons.
