Class 11 Chemistry - Chapter Structure of Atom NCERT Solutions | Following results are observed when sodi
Following results are observed when sodium metal is irradiated with different wavelengths.
Calculate (a) threshold wavelength and, (b) Planck’s constant.
| λ (nm) | 500 | 450 |
400 |
| v × 10–5 (cm s–1) | 2.55 | 4.35 | 5.35 |
(a) Let us suppose threshold wavelength to be λD nm (= λ0 x 10-9 m), the kinetic energy of the radiation is given as:
h(v-v0)=1/2 mv2
Or
hc(1/λ - 1/λD) = 1/2 mv2
Threshold wavelength (λD)= 540 nm
Substituting this value in equation iii,we get
= h x (3x108)/10-9 [1/400-1/540]
= [(9.11x10-31)(5.20x106)2] / 2
=6.66x10-34Js
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4 Comment(s) on this Question
An excellent solution.
Thank you
Hey you have copied wrong values in second case it's 4.35 not 3.45
Somehow answer is git by you Nothing explained clearly 1st you should take threshold wevelength from let then put photoelectric formulae then put values avg. Of given data
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