Ncert Solutions Chemistry Class 11th
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New answer posted
5 months agoContributor-Level 10
This is a Long Answer Type Questions as classified in NCERT Exemplar
Ans: We have
v= 109677 [1/ni 2 - 1/nf 2 ]
Given, ni = 3 and nf =2
D E= hcv = 109677 [1/ni 2 - 1/nf 2 ]
DE = - 3.052 * 10-19J
n =DE /h= 4.606 * 1016Hz
New answer posted
5 months agoContributor-Level 10
This is a Long Answer Type Questions as classified in NCERT Exemplar
Ans: The points of the Bohr's model that can be consider are as follows: -
(i) Electrons revolve around the nucleus in a fixed orbit with fixed energy
(ii) The energy is absorbed or released when the electron moves from one energy level to another. The energy for the nth stationary state is given by
En = -2 p 2me4 /n2h2
Where
m = mass of the electron
e = charge of the electron
h= Planck's constant If an electron jumps from ni to nf then we have
D E= Ef - Ei = 2p2me4 /h2 [ (1/ni 2 ) - (1/nf2 )]
v = DE /hc = 109677 [ (1/ni 2 ) - (1/nf2 )]
New answer posted
5 months agoContributor-Level 10
This is a Long Answer Type Questions as classified in NCERT Exemplar
ANS- For the emission of electrons from metal the frequency of the striking light should be higher than that of its threshold frequency. We have
h ν = hν 0 + K.E
ν 0 = ν - K.E/h ……. (1)
Given
ν = 1015 s -1, K.E = 1.988 X 10-19J
Thus (1) gives
ν 0 = 7 x 1014 s -1
Given
λ = 600 nm
ν = c/ λ = 5 x 1014 s -1
As ν 0 > ν, thus the electrons do not emit.
New answer posted
5 months agoContributor-Level 10
This is a Long Answer Type Questions as classified in NCERT Exemplar
ANS-When the beam of light gets exposed to the metal surface then the electrons get emitted from the metal. This effect is said to be photoelectric effect and the emitted electrons are said to be photoelectrons. The result of photoelectric experiment are as follows: -
(i) There is no time gap between the striking of a light beam and the ejection of electrons from the metal surface i.e., electrons emit as soon as a beam of light strikes the metal surface.
(ii) The number of electrons ejected is directly proportional to the intensity of light.
(iii) For every metal there
New answer posted
5 months agoContributor-Level 10
This is a Matching Type Questions as classified in NCERT Exemplar
i d + 48
ii a &n
New question posted
5 months agoNew answer posted
5 months agoContributor-Level 10
This is a Matching Type Questions as classified in NCERT Exemplar
i ) b 1681 3374 – 328
ii ) a 419 3051 – 48
iii)
New answer posted
5 months agoContributor-Level 10
This is a Matching Type Questions as classified in NCERT Exemplar
Be 111
C
New answer posted
5 months agoContributor-Level 10
This is a Assertion and Reason Type Questions as classified in NCERT Exemplar
Option (ii)
The electron gain enthalpy decreases down the group due to the increase in the atomic size which leads to decrease in the effective nuclear charge.
New answer posted
5 months agoContributor-Level 10
This is a Assertion and Reason Type Questions as classified in NCERT Exemplar
Option (iii)
The Be has the electronic configuration of [He]2s2 while B has the electronic configuration of [He]2s22p1 . As in Be the outermost orbital i.e. 2s is fully filled thus it provides extra stability to the Be compared to B. Apart from this 2s electron is more penetrated compared to the 2p electron for which 2p electron faces more shielding effect than that of 2s electron.
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