Two long, straight wires are fixed parallel to one another a distance do apart. The wires carry equal constant currents 1, in the same direction. The attractive magnetic force per unit length between them if f = F/L. What is the force per unit length between the wires if their separation is 2d, and each carries current 210? 10 da lo A. f/4 B. f/2 C. 3f/2 D. 2f

The option (B) is correct.

Explanation:

The magnetic force between the two current carrying wires is given by

where,  I and I' be the currents in the wires and r is the distance between the two wires.

Here, we observe that the force between the wires is inversely proportional to the distance between them.

So, when the distance is doubled , let the new force is F'.

So, option (B) is correct.

the total distance traveled by the car is

30km + 49km = 79 km .

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 =