Question

a platinum wire of length 5cm & diameter 1 mm
is at 200k. Assuming that it radiates like a
black body, find the rate at which it is
loosing energy,
S.C-6 -5.67x100 win it
PRE​

Answer 1

Given info : A platinum wire of length 5cm and diameter 1mm is at 200K. Assuming that it radiates like a black body.

To find : the rate at which losing energy of platinum wire.

Solution : rate of loosing energy, dQ/dt = P = σeAT⁴

Where, σ is Stefan Boltzmann's constant i.e., σ = 5.67 × 10^-8 W/m²K⁴

e is emissivity, for black body, e = 1

And A is surface area.

I.e., A = 2πrl = 2 × 3.14 × 10¯³/2 × 5 × 10¯² m²

= 15.7 × 10¯⁵ = 1.57 × 10¯⁴ m²

So, P = 5.67 × 10^-8 × 1 × 1.57 × 10¯⁴ × (200)⁴

= 0.01424 W

therefore the rate at which it is loosing energy is 0.01424 W