The ionisation energy of hydrogen is 13.6 eV . The energy of the photon released when an electron jumps from the first excited state (n=2) to the ground state of hydrogen atom is
A. 3.4 eV
B. 4.53 eV
C. 10.2 eV
D. 13.6eV
Correct Answer - C
The energy rquired to removed electron in the first excited state (n=2)
The energy of the photon `Rhc((1)/(1^(2))-(1)/(n^(2)))`
`rArr" " 13.6((1)/(4)-(1)/(4))=13.6((4-1)/(4))`
`" " =13.6 xx(3)/(4)=(40.8)/(4)=10.2eV`
Given ,total energy of the electron `E=-4.6 EV`
(i) Kinetic energy of electron K=-(Total energy E,)
`rArr " " =-E=-(-4.6)=4.6 eV`
(ii) de- Brogile wavelength
`lambda_(d)=(h)/(sqrt(2 mK))=(6.6xx10^(-34))/(sqrt(2xx9.1xx10^(-31)xx4.6xx1.6xx10^(-19)))`
`0.57xx10^(-9)m=0.57 nm`
Correct Answer - A
(A)For `Li^(2+)`, n=6 to n=3
For H, the similar transition is 2 to 1
For `He^+` , the similar transition is 4 to 2
Energy of `4^(th)`...
Correct Answer - D
In ground state , kinetic energy `= 13.6 eV`, Potential energy `= -27.2 eV`
In first excited state, kinetic energy `= 3.4 eV`, Potential energy `= -...
Correct Answer - B
`E_(1) = (hc)/(lambda) [(1)/(n_(1)^(2)) - (1)/(n_(2)^(2))]`
For second excited state to first excited state
`E_(1) = (hc)/(lambda) [1/4 - 1/9] rArr (hc)/(lambda) ((5)/(36))`
For first excited state...
Correct Answer - A
`10= .^(n)C_(2) implies n=5`, then 5 orbits are involved upon coming to second excited state
so `n^(th)` excited state is `6^(th) [2^(nd), 3^(rd), 4^(th), 5^(th), 6^(th)]`
Correct Answer - B
Mole of `H_(2)` present in one litre `=(PV)/(RT)=(1xx1)/(0.0821xx298)=0.0409`
Thus, energy needed to break H-H bonds in `0.0409` mole `H_(2)=0.0409xx436=17.83 kJ`.
Also energy needed to excite one H...