A 0.65-T magnetic field is perpendicular to a circular loop of wire with 73 turns and a radius of 18 cm. If the magnetic field is reduced to zero in 0.12 s, what is the magnitude of the induced emf?

conservation of mass

mass before something happens = mass afterwards

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.

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 =