KCET · Physics · Nuclear Physics
The energy (in eV) required to excite an electron from \( n=2 \) to \( n=4 \) state in hydrogen atom is
- A + \( 2.55 \)
- B - \( 3.4 \)
- C \( -0.85 \)
- D + \( 4.25 \)
Answer & Solution
Correct Answer
(A) + \( 2.55 \)
Step-by-step Solution
Detailed explanation
In a hydrogen atom, energy required to excite an electron from state \(E_{1}\) to state \(E_{f}\) is \(E=E_{f}-E_{i}\)
where energy of a state \(\mathrm{n}\) is given by
\[
\begin{array}{l}
E_{n}=\frac{-13.6}{n^{2}} \mathrm{eV} \\
E_{4}=\frac{-13.6}{42}=\frac{-13.6}{16}=-0.85 \mathrm{eV} \\
\text { and } E_{2}=\frac{-13.6}{2^{2}}=\frac{-13.6}{4}=-3.4 \mathrm{eV}
\end{array}
\]
Therefore,
\[
E=E_{4}-E_{2}=-0.85-(-3.4)=(3.4-0.85) e \mathrm{~V}
\]
Thus, energy required \(=2.55 \mathrm{eV}\)
where energy of a state \(\mathrm{n}\) is given by
\[
\begin{array}{l}
E_{n}=\frac{-13.6}{n^{2}} \mathrm{eV} \\
E_{4}=\frac{-13.6}{42}=\frac{-13.6}{16}=-0.85 \mathrm{eV} \\
\text { and } E_{2}=\frac{-13.6}{2^{2}}=\frac{-13.6}{4}=-3.4 \mathrm{eV}
\end{array}
\]
Therefore,
\[
E=E_{4}-E_{2}=-0.85-(-3.4)=(3.4-0.85) e \mathrm{~V}
\]
Thus, energy required \(=2.55 \mathrm{eV}\)
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Physics
- Wavefront is the locus of all points, where the particles of the medium vibrate with the sameKCET 2011 Easy
- A spherical conductor of radius \( 2 \mathrm{~cm} \) is uniformly charged with \( 3 \mathrm{nC} \). What is the electric field at a distance of \( 3 \mathrm{~cm} \) from the center of the sphere?KCET 2014 Medium
- See the diagram. Area of each plate is \(2.0 \mathrm{~m}^{2}\) and \(d=2 \times 10^{-3} \mathrm{~m}\). A charge of \(8.85 \times 10^{-8} \mathrm{C}\) is given to \(Q\). Then the potential of \(Q\) becomes
KCET 2013 Easy - A parallel place capacitor is charged by connecting a \(2 \mathrm{~V}\) battery across it. It is then disconnected from the battery and a glass slab is introduced between plates. Which of the following pairs of quantities decrease?KCET 2022 Medium
- A \(220 \mathrm{~V}\) AC supply is connected between points \(A\) and \(B\) as shown in figure, what will be the potential difference \(V\) across the capacitor?
KCET 2020 Easy - In the circuit given here, the points A, B and \(C\) are \(70 \mathrm{~V}\), zero, \(10 \mathrm{~V}\) respectively. Then
KCET 2010 Medium
More PYQs from KCET
- The major product of the following reaction is \(\mathrm{CH}_{2}=\mathrm{CH}-\mathrm{CH}_{2}-\mathrm{OH} \underset{\text { Excess }}{\stackrel{\mathrm{HBr}}{\longrightarrow}}\) ProductKCET 2021 Medium
- Which among the following products of microbes is not obtained from fungi?KCET 2021 Hard
- \(\int^{e^{x} \cdot x^{5}} d x\) isKCET 2008 Hard
- A man speaks truth \( 2 \) out of \( 3 \) times. He picks one of the natural numbers in the set \( S=\{1,2, \),
\( 3,4,5,6,7\} \) and reports that it is even. The probability that it is actually even isKCET 2019 Easy - The sum of \( 1^{s t} \mathrm{n} \) terms of the series
\[
\frac{1^{2}}{1}+\frac{1^{2}+2^{2}}{1+2}+\frac{1^{2}+2^{2}+3^{2}}{1+2+3}+\ldots
\]KCET 2016 Hard - The statement that is NOT correct isKCET 2014 Medium