Power dissipated in the filament

(P) = I²R (in watt)

Volume of the material

of the filament

(v) = πr²l (in m³)

Surface area of the

tungsten filament

(A) = 2πrl (in m²)

6

3.8032 × 10⁻¹¹

0.0000133095

10

8.9620 × 10⁻¹¹

0.0000220462

25

4.0000 × 10⁻¹⁰

0.0000539674

40

3.0000 × 10⁻¹⁰

0.0000395031

60

9.0000 × 10⁻¹⁰

0.0000765753

100

1.8000 × 10⁻⁹

0.0001154707

200

4.6000 × 10⁻⁹

0.0001924512

300

9.2000 × 10⁻⁹

0.0002886768

500

2.2300 × 10⁻⁸

0.0004947820