Question

Which of the following statements is/are true in case of an incandescent filament bulb?

1. (a) Filament can be made of tungsten or nichrome.
2. (b) The glass envelope covering the filament is filled with inactive gases such as nitrogen or argon.
3. (c) Since the filament used is thin, its resistivity is very low.
4. (d) The resistivity of the filament is low to allow more current.
5. (e) The filament material used should have high melting point.

• A. 1, 2, 5
• B. None of these
• C. All
• D. 2 only

Answer 1

Answer:

A. 1, 2, 5

• The true statements regarding an incandescent filament bulb are:

• (a) Filament can be made of tungsten or nichrome.

• While tungsten is most commonly used due to its high melting point, nichrome, an alloy of nickel and chromium, can also be used.

• (b) The glass envelope covering the filament is filled with inactive gases such as nitrogen or argon.

• These gases prevent the tungsten filament from evaporating and oxidizing, thus prolonging its life.

• (e) The filament material used should have a high melting point.

• This allows the filament to withstand the high temperatures generated when it glows.