Answer:
Magnetic force, [tex]F=9.13\times 10^{-10}\ N[/tex] from north to south.
Explanation:
It is given that,
Mass of the ball, m = 140 g = 0.14 kg
Number of electrons, [tex]n=4.1\times 10^8[/tex]
Height, h = 110 m
Charge, q = ne
[tex]q=4.1\times 10^8\times 1.6\times 10^{-19}=6.56\times 10^{-11}\ C[/tex]
Magnetic field, B = 0.3 T
The potential energy at height of 110 meters is balanced by the kinetic energy as per the law of conservation of energy as :
[tex]mgh=\dfrac{1}{2}mv^2[/tex]
[tex]v=\sqrt{2gh}[/tex]
[tex]v=\sqrt{2\times 9.8\times 110}=46.43\ m/s[/tex]
Magnetic force is given by :
F = q v B
[tex]F=6.56\times 10^{-11}\times 46.43\times 0.3[/tex]
[tex]F=9.13\times 10^{-10}\ N[/tex]
As the direction of magnetic field is from east to west, so from right hand thumb rule the direction of magnetic force is from north to south. Hence, this is the required solution.
