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Question
For the ground state, the electron in the H-atom has an angular momentum = h, according to the simple Bohr model. Angular momentum is a vector and hence there will be infinitely many orbits with the vector pointing in all possible directions. In actuality, this is not true ______.
Options
because Bohr model gives incorrect values of angular momentum.
because only one of these would have a minimum energy.
angular momentum must be in the direction of spin of electron.
because electrons go around only in horizontal orbits.
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Solution
For the ground state, the electron in the H-atom has an angular momentum = h, according to the simple Bohr model. Angular momentum is a vector and hence there will be infinitely many orbits with the vector pointing in all possible directions. In actuality, this is not true because Bohr model gives incorrect values of angular momentum.
Explanation:
Bohr found that the magnitude of the electron’s angular momentum is quantized i.e. L = `mv_nr_n = n(h/(2pi))` where n = 1, 2 , 3, ...... each value of n corresponds to a permitted value of the orbit radius. rn = Radius of nth orbit, vn = corresponding speed
Bohr’s model gives only the magnitude of angular momentum. The angular momentum is a vector quantity. Hence we cannot express angular momentum completely by the Bohr model. Hence it does not give correct values of angular momentum of a revolving electron.
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