Question

One gram hydrogen has $6\times {10}^{23}$ atoms. Imagine that all the nuclei are put at the north pole of the earth and the electrons at the south pole of the earth (radius=6400 km). The force between the charges is

• A. $10\times {10}^{5}N$
• B. $5\times {10}^{5}N$
• C. $2.5\times {10}^{5}N$
• D. $2\times {10}^{5}N$

Answer 1

The correct option is A $10\times {10}^{5}N$

Given: Mass of hydrogen= 1 gram ;Radius=6400 km

To Find: Forces between charges

Solution : No of mole=$\frac{weight}{molecularweight}=\frac{1}{2}$

No of electrons and protons=$2\ast \frac{1}{2}\ast 6\ast {10}^{23}$

=$6\ast {10}^{23}$

Charge(q)=ne=$1.6\ast {10}^{-19}\ast 6\ast {10}^{23}$

=960000

Force=${\frac{kq}{r^2}}^2$

=$\frac{9\ast {10}^{{}^9}\ast \{9.6\ast {10}^4{\}}^2}{{6400}^2}$

=$10\ast {10}^5$N

Answer: Hence option A is correct