00:01
All right everyone, in this question we are given the radius of an orbit which you take as r equal to 5 .29 multiplied by 10 to minus 11 meter of an electron of a hydrogen atom which moves or revolves around a proton in the board theory of hydrogen atom.
00:25
So if you take the charge of the electron which is q1, it is equal to 1 .6 multiplied by 10 to per 1.
00:33
Minus 19 coulum similarly the charge of proton if we take us q2 is equal to 1 .6 multiplied by 10 to 10 to 10 minus 19 coulum when we take the charges of electron and proton we have considered only the magnitude of the charges in part of the question we are asked to find out the magnitude of the electric force that is exerted on each particle we take the electric force to be f and it is given by k which is a constant multiplied by u1 multiplied by q2 divided by r square this comes from coulum's law here r will be the distance between the electron and the proton and this r is constant since the electron is revolving around the proton the electric force f will be equal to the constant k is 9 times 10 to part 9 multiplied by u1 is 1 .6 multiplied by to the power minus 19 coulum and q2 is also 1 .6 multiplied by 10 to the minus 19 coulum divided by r square you have the value of r which is 5 .29 multiplied by 10 to the per minus 11 the square of that and if we calculate this we get the force to be equal to 8 .22 multiplied by 10 to the power minus 8 newton therefore the electric force which is exerted on each particle is 8 .22 multiplied by 10 to the power minus 8 newton and so you have the answer of the first part of the question we now come to the second part which is part b in the part b we were asked to find out the speed of the electron which we take as v since the electron is revolving around the proton that means the electron is under circular motion.
02:46
The electron being under circular motion implies that it experiences a centripetal.
02:56
A centripetal force is a force which acts on a body which is moving in a circle.
03:01
And the direction of the centripetal force is towards the center of the circle.
03:05
Now since this electron is revolving around the proton, that means the centripetal force should be equal to the electric force which is f.
03:14
If this equilibrium condition is not satisfied, then the electron will not revolve around the proton because both have opposite polarity and they'll attract each other so these forces being equal the electron will revolve around the proton the centripetal force is given by the mass of the electron multiplied by square of the speed divided by radius of the orbit are equal to the force f which is 8 .22 multiplied by 10 to 0 .2m...