JEE Mains · Physics · STD 12 - 12. atoms
The electron in a hydrogen atom first jumps from the third excited state to the second excited state and subsequently to the first excited state. The ratio of the respective wavelengths, \(\lambda _1/\lambda _2\), of the photons emitted in this process is
- A \(20/7\)
- B \(7/5\)
- C \(9/7\)
- D \(27/5\)
Answer & Solution
Correct Answer
(A) \(20/7\)
Step-by-step Solution
Detailed explanation
\(\frac{1}{\lambda } = R\left( {\frac{1}{{n_f^2}} - \frac{1}{{n_i^2}}} \right);\) \(\frac{1}{{{\lambda _1}}} = R\left( {\frac{1}{{{3^2}}} - \frac{1}{{{4^2}}}} \right)\) \(\frac{1}{{{\lambda _1}}} = R\left( {\frac{7}{{9 \times 16}}} \right);\)…
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
- A solid sphere of mass \(M\) and radius \(R\) is divided into two unequal parts. The first part has a mass of \(\frac {7M}{8}\) and is converted into a uniform disc of radius \(2R.\) The second part is converted into a uniform solid sphere. Let \(I_1\) be the moment of inertia of the disc about its axis and \(I_2\) be the moment of inertia of the new sphere about its axis. The ratio of \(I_1/I_2\) is given byJEE Mains 2019 Hard
- A man carrying a monkey on his shoulder does cycling smoothly on a circular track of radius \(9 \mathrm{~m}\) and completes \(120\) revolutions in \(3\) minutes. The magnitude of centripetal acceleration of monkey is _______ (in \(\mathrm{m} / \mathrm{s}^2\) ).JEE Mains 2024 Hard
- A person of mass \(M\) is, sitting on a swing of length \(L\) and swinging with an angular amplitude \(\theta_0\). If the person stands up when the swing passes through its lowest point, the work done by him, assuming that his centre of mass moves by a distance \(l\, ( l < < L)\), is close toJEE Mains 2019 Hard
- A solid steel ball of diameter 3.6 mm acquired terminal velocity \(2.45 \times 10^{-2} \mathrm{~m} / \mathrm{s}\) while falling under gravity through an oil of density \(925 \mathrm{~kg} \mathrm{~m}^{-3}\). Take density of steel as \(7825 \mathrm{~kg} \mathrm{~m}^{-3}\) and g as 9.8 \(\mathrm{m} / \mathrm{s}^2\). The viscosity of the oil in SI unit isJEE Mains 2025 Medium
- Match the thermodynamic processes taking place in a system with the correct conditions. In the table: \(\Delta Q\) is the heat supplied, \(\Delta W\) is the work done and \(\Delta U\) is change in internal energy of the system
Process Condition \((I)\) Adiabatic \((A)\; \Delta W =0\) \((II)\) Isothermal \((B)\; \Delta Q=0\) \((III)\) Isochoric \((C)\; \Delta U \neq 0, \Delta W \neq 0 \Delta Q \neq 0\) \((IV)\) Isobaric \((D)\; \Delta U =0\) JEE Mains 2020 Medium - If \(Y, K\) and \(\eta\) are the values of Young's modulus, bulk modulus and modulus of rigidity of any material respectively. Choose the correct relation for these parameters.JEE Mains 2021 Medium
More PYQs from JEE Mains
- Statement \(-1 :\) The value of the integral \(\mathop \smallint \limits_{\frac{\pi }{6}}^{\frac{\pi }{3}} \frac{{dx}}{{1 + \sqrt {\tan x} }} = \frac{\pi }{6}\) Statement \(-2 :\) \(\;\mathop \smallint \limits_a^b {\rm{f}}\left( {\rm{x}} \right)dx = \mathop \smallint \limits_a^b {\rm{f}}\left( {a + b - x} \right)\;dx\)JEE Mains 2013 Medium
- The electric current in the circuit is given as \(i=i_{ o }(t / T)\). The r.m.s current for the period \(t=0\) to \(t=T\) is ___________JEE Mains 2026 Easy
- Suppose \(a_1, a_2, 2, a_3, a_4\) be in an arithmeticogeometric progression. If the common ratio of the corresponding geometric progression is \(2\) and the sum of all \(5\) terms of the arithmetico-geometric progression is \(\frac{49}{2}\), then \(a_4\) is equal to \(...........\).JEE Mains 2023 Hard
- A train is moving with a speed of \(12 \mathrm{~m} / \mathrm{s}\) on rails which are \(1.5 \mathrm{~m}\) apart. To negotiate a curve radius \(400 \mathrm{~m}\), the height by which the outer rail should be raised with respect to the inner rail is (Given, \(g=\) \(10 \mathrm{~m} / \mathrm{s}^2\) ) :JEE Mains 2024 Hard
- Two cars \(P\) and \(Q\) are moving on a road in the same direction. Acceleration of car \(P\) increases linearly with time whereas car \(Q\) moves with a constant acceleration. Both cars cross each other at time \(t=0\), for the first time. The maximum possible number of crossing(s) (including the crossing at \(t=0)\) is ________.JEE Mains 2025 Medium
- In a potentiometer arrangement, a cell of emf \(1.20\, V\) gives a balance point at \(36\, cm\) length of wire. This cell is now replaced by another cell of emf \(1.80\, V\). The difference in balancing length of potentiometer wire in above conditions will be \(....cm\).JEE Mains 2022 Hard