ChemTopper Free Chemistry Help

de-Broglie wavelength of electron in second orbit will be equal to de-Broglie wavelength of
a) n=3 of H-atom
b) n=4 of Cl+5 ion
c) n=3 of He+ ion
d) n=6 of Be3+ ion

Velocity of electron in Bohr's orbit is given by
first postulates of Bohr's theory
mvr =nh/2π
n is the number of orbit
Reaarange above equation
r= nh/2πv-- ---  (1)

Second postulates gives radius

Now  r = n²h²/4π²me²KZ------(2)

Equating equation 1 and 2
V=  2π² Kme² Z/nh
Now here all are constant except Z and n so it means velocity is directly proportional to Z /n
           V α Z/n
Now you can calculate Z/n ratio for ions mentioned in the questions
Z is nuclear charge (atomic number)  and n is the shell number

Electrons with same Z/n ratio will have same velocity