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JEE Main 202623 JanuaryEvening Shift
Exam
JEE Main
Year
2026
Date
23 January
Shift
Evening Shift
Subject
Chemistry
Chapter
Structure of Atom

JEE Main 2026 · 23 January · Evening Shift · Chemistry · Structure of Atom

Identify the INCORRECT statements from the following: A. Notation _...

Identify the INCORRECT statements from the following:
A. Notation 1224Mg{ }_{12}^{24} \mathrm{Mg} represents 24 protons and 12 neutrons.
B. Wavelength of a radiation of frequency 4.5×1015 s−14.5 \times 10^{15} \mathrm{~s}^{-1} is 6.7×10−8 m6.7 \times 10^{-8} \mathrm{~m}.
C. One radiation has wavelength =λ1(900 nm)=\lambda_{1}(900 \mathrm{~nm}) and energy =E1=\mathrm{E}_{1}. Other radiation has wavelength =λ2(300 nm)=\lambda_{2}(300 \mathrm{~nm}) and energy =E2.E1:E2=3:1=\mathrm{E}_{2}. \mathrm{E}_{1}: \mathrm{E}_{2}=3: 1.
D. Number of photons of light of wavelength 2000 pm that provides 1 J of energy is 1.006×10161.006 \times 10^{16}.
Choose the correct answer from the options given below:

Options

  1. AB and C Only
  2. BA and D Only
  3. CA and C Only
  4. DA and B Only

Correct answer

C. A and C Only

Step-by-step solution

Checking each statement:
(A) states 1224Mg_{12}^{24}Mg has 24 protons, but the mass number is 24 and atomic number is 12, so this is INCORRECT.
(B) Using λ=cf=3×1084.5×1015=6.67×10−8\lambda = \frac{c}{f} = \frac{3 \times 10^8}{4.5 \times 10^{15}} = 6.67 \times 10^{-8} m, which is CORRECT.
(C) For λ1=900\lambda_1 = 900 nm and λ2=300\lambda_2 = 300 nm, since energy is inversely proportional to wavelength, E1:E2=1:3E_1:E_2 = 1:3, not 3:13:1 as stated, so this is INCORRECT.
(D) For photons at λ=2000\lambda = 2000 pm, energy per photon is E=hcλ=9.94×10−17E = \frac{hc}{\lambda} = 9.94 \times 10^{-17} J, giving N=1.006×1016N = 1.006 \times 10^{16} photons for 1 J, which is CORRECT.
The incorrect statements are A and C.
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