A heater rod (10 mm diameter, 100 mm length) of emissivity 0.75 is enclosed within a hollow cylindrical vacuum chamber (50 mm diameter, 100 mm length) of emissivity 0.25. The entire setup is insulated at the top and bottom ends by a low emissivity material, preventing any conductive heat dissipation from the ends. The heater rod is known to have a surface temperature of 1000 K, while the vacuum chamber is at a surface temperature of 300 K. How much heat is dissipated from the heater rod to the vacuum chamber (W)

Explanation:

Given that:

Heater temperature ,T₁ = 1000K

Vaccum Chamber ,T₂ = 300K

emissivity of heater E₁ = 0.75

emissivity vaccum E₂ = 0.25

Heater diameter d₁ = 10 * 10⁻³mm

vaccum chamber d₂ = 50 * 10⁻³mm

When there is vaccum, then no air resistance will be there,

F₁₂ = 1

F₁₁ = 0

Heat leaving from heater surface 1 to vaccum

a.metals can become magnetic if they have many spinning electrons that create magnetic fields.d.only some metals are attracted by magnets; these metals are called ferromagnetic.

d.wrapping an insulated wire around a metal with ferromagnetic properties and applying an electric current.

no simpler subs form complex ones. synthesise = make