Q. 104.3( 7 Votes )

Suppose all the electrons of 100g water are lumped together to form a negatively charged particle and all the nuclei are lumped together to form a positively charged particle. If these two particles are placed 10.0 cm away from each other, find the force of attraction between them. Compare it with your weight.

Answer :


Mass of water ,

Molar mass of water

Moles of water in 100g of water =

Number of electrons in 1 molecule of water = 2 times one electron each in hydrogen atom + 8 electrons in oxygen atom = 10 electrons


Formulas used:

The relation between molar mass M, mass of sample m and number of moles of sample n is given by:

1 mol of “something” contains NA number of “something”.


Number of electrons in 1 mol of electrons =

Number of electrons in 100 g of water

Negative charge on one electron =

Total negative charge

We have,


Distance of separation,


Formula used:

By Coulomb’s law, the electric force is given by:

Where ϵ0 is the permittivity of free space

k is the electrostatic constant

q1 and q2 are the magnitude of charges

r is the distance of separation between the charges


The magnitude of electric force is:

Let my mass m be 70 kg.

The electric force between the two charges is about 1022 times my weight!

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