Question 527: Atoms & Nuclei

Question

Consider 3
rd
orbit of He
+
(Helium), using non-relativistic approach, the speed of electron in this orbit will be [given K = 9 $$ 	imes $$ 10
9
constant, Z = 2 and h (Planck's Constant) = 6.6 $$ 	imes $$ 10
$$-$$34
J s]

Accepted Answer

Energy of electron in He
+
3
rd
orbit
E
3
= -13.6 $$ 	imes $$ $${4 \over 9}eV$$
= -13.6 $$ 	imes $$ $${4 \over 9}$$ $$ 	imes $$ 1.6 $$ 	imes $$ 10
-19
J
= - 9.7 $$ 	imes $$ 10
-19
J
According to BohrÃ¢ÂÂs model,
Kinetic energy of electron in the 3
rd
orbit = Ã¢ÂÂ E
3
$$ 	herefore $$ 9.7 $$ 	imes $$ 10
-19
= $${1 \over 2}{m_e}{v^2}$$
v = $$\sqrt {{{2 	imes 9.7 	imes {{10}^{19}}} \over {9.1 	imes {{10}^{ - 31}}}}} $$ = 1.46 $$ 	imes $$ 10
6
m/s

Answer

0.73 $$ 	imes $$ 10
6
m/s

Answer

3.0 $$ 	imes $$ 10
8
m/s

Answer

2.92 $$ 	imes $$ 10
6
m/s

Answer

1.46 $$ 	imes $$ 10
6
m/s

Atoms & Nuclei

Consider 3 rd orbit of He + (Helium), using non-relativistic approach, the speed of electron in this orbit will be [given K = 9 $ \times 10 9 constant, Z = 2 and h (Planck's Constant) = 6.6 \times 10 -$34 J s]

Choose the correct answer: