Question

The speed of electron in the first Bohr Orbit of H atom is :

i) c / 1.37

ii) c / 1370

iii ) c / 13.7

iv ) c / 137

Here C refers to the speed of light.

Chapter : Structure of Atoms
Class : 11

Answer needed with the required calculations !!

Answer 1

We know that,

Velocity of an electron in Bohr's Orbit is given by Following euqation:-

v =( 2πe²Z)/hñ

After putting all values Final formula comes as ;
v = 2.18 ×z/n

Where z is atomic number and n is Orbital number

For H atom z = 1

For first orbital n= 1

We get,
v = 2.19 × 10^6 m/sec
Refer to attachment for calculations;-)

Note:- Unit of velocity should be mentioned in question!

Answer 2

HEYA MATE !!!
I'LL TRY TO SOLVE...
________________....
By using the formula for velocity of electron in shell we can apply :-
V(in nth shell) = 2.18×10^6 Z/n
where ; Z = atomic no.
n = no. of shell..
V = 2.18 × 10^6 m/sec.
now,
If we say
2.18 × 10^ 6 = c/x
==> 2.18 × 10^6 = 3 × 10^8 m/s. /x
===> x = 3 × 10^8 / 2.18 × 10^6

===> x = 1.376 × 10^2
x = 137.6
so answer = 137 ( 4th option)

thanks moderator for giving me second chance of attempt...

*proudly Indian*