Answer:
Length L=0.0125 m
Step-by-step explanation:
Given data
Resistance R=0.11Ω
Temperature T=20°C
Resistivity of tungsten at 20°C p=5.6×10⁻⁸Ω.m²
Radius of filament r=0.09/2 =0.045 mm =0.045×10⁻³m
To find
Length of filament L
Solution
The Cross section of area of filament is given as:

The Resistance of a material is given as:
