If the earth-sun distance were doubled, the intensity of radiation from the sun that reaches the earth's surface would if the earth-sun distance were doubled, the intensity of radiation from the sun that reaches the earth's surface would

a. quadruple.
b. double.
c. drop to 14.
d. drop to 12.

option C

Explanation:

given,                                                                

the  Earth-Sun distance were doubled                

intensity of radiation is inversely proportional to d²

                 I₀ ∝

if the distance is doubled then                    

                 I ∝

                 I ∝              

                 I ∝

                 I ∝ I₀

hence, the correct answer is option C

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 =

prndulum needs thread, weight clock to time swings