Consider a blackbody that radiates with an intensity I1I1I_1 at a room temperature of 300K300K. At what intensity I2I2I_2 will this blackbody radiate when it is at a temperature of 400K400K

Explanation:

We shall apply Stefan's formula

E = AσT⁴

When T = 300

I₁ = Aσ x 300⁴

When T = 400K

I₂ = Aσ x 400⁴

I₂ / I₁ = 400⁴ / 300⁴

= 256 / 81

= 3.16

I₂ = 3.16 I₁ .

it is given that trillions of microbes make up to 1% to 3% of the body mass.

let's take average of this percentage: 2%

consider the average mass of the human body as 70 kg.

then, trillions of microbes would have mass  

therefore, 100 trillion micro-organisms would weigh:

this is an approximate value and could change depending on the mass of the human body and percentage of the microbes present in it.

average mass per microorganism =