The degree of hardness of water is usually expressed in terms of
- ppm by weight of $MgSO_{4}$
- $g/L$ of $CaCO_{3}$ and $MgSO_{3}$ present
- $ppm$ by weight of $CaCO_{3}$ irrespective of whether it is actually present
- $ppm$ of $CaCO_{3}$ actually present in water
The Correct Option is C
Solution and Explanation
Top Questions on Bohr’s Model for Hydrogen Atom
- Match List I with List II.Choose the correct answer from the options given below:
List I
(Spectral Lines of Hydrogen for transitions from)List II
(Wavelength (nm))A. n2 = 3 to n1 = 2 I. 410.2 B. n2 = 4 to n1 = 2 II. 434.1 C. n2 = 5 to n1 = 2 III. 656.3 D. n2 = 6 to n1 = 2 IV. 486.1 - NEET (UG) - 2024
- Physics
- Bohr’s Model for Hydrogen Atom
- For hydrogen atom, energy of an electron in first excited state is $-3.4 \, \text{eV}$, K.E. of the same electron of hydrogen atom is $x \, \text{eV}$.Value of $x$ is ____ $\times 10^{-1} \, \text{eV}$. (Nearest integer)
- JEE Main - 2024
- Chemistry
- Bohr’s Model for Hydrogen Atom
- In Franck-Hertz experiment, the first dip in the current-voltage graph for hydrogen is observed at 10.2 V. The wavelength of light emitted by hydrogen atom when excited to the first excitation level is _____ nm.
(Given $hc = 1245 \, \text{eV nm}, \, e = 1.6 \times 10^{-19} \, \text{C}$).- JEE Main - 2024
- Physics
- Bohr’s Model for Hydrogen Atom
- According to Bohr's theory, the moment of momentum of an electron revolving in the 4th orbit of a hydrogen atom is:
- JEE Main - 2024
- Physics
- Bohr’s Model for Hydrogen Atom
- The spin-orbit interaction in a hydrogen-like atom is given by the Hamiltonian \( H' = -k \vec{L} \cdot \vec{S} \), where \( k \) is a real constant. The splitting between levels \( ^2P_{3/2} \) and \( ^2P_{1/2} \) due to this interaction is _______.
- GATE PH - 2024
- Atomic and Molecular Physics
- Bohr’s Model for Hydrogen Atom
Questions Asked in AMUEEE exam
- The ratio of the half-life time $ (t_{1/2}) $ , to the three quarter life-time, $ (t_{3/4}) $ , for a reaction that is second order
- AMUEEE - 2018
- Order of Reaction
- $ 0.002\, M $ solution of a weak acid has an equivalent conductance $ (\wedge) 60\, ohm^{-1}\, cm^{2}\, eq^{-1} $ . What will be the $ pH $ ? (Given : $ \wedge = 400 \, ohm^{-1} \, cm^{2} \, eq^{-1} $ ]
- AMUEEE - 2018
- Electrochemistry
- The electrode potential, $ E^{\circ} $ , for the reduction of $ MnO^{-}_{4} $ to $ Mn^{2+} $ in acidic medium is $ +1.51\, V $ . Which of the following metal(s) will be oxidised? The reduction reactions and standard electrode potentials for $ Zn^{2+}, Ag^{+} $ , and $ Au^{+} $ are given as $ Zn^{2+} (aq) +2e \to Zn(s), E^{\circ} = -0.762\, V $ $ Ag+ (aq) +e {\rightleftharpoons} Ag (s), E^{\circ}=+0.80 \,V $ $ Au^{+} (aq) +e {\rightleftharpoons} Au(s), E^{\circ}+1.69\,V $
- AMUEEE - 2018
- Electrochemistry
- Three particles, two with masses $ m $ and one with mass $ M $ , might be arranged in any of the four configurations shown below. Rank the configurations according to the magnitude of the gravitational force on $ M $ , least to greatest
- AMUEEE - 2018
- Gravitation
- The $ EAN $ value $ y \left[Ti\left(\sigma-C_{6}H_{5}\right)_{2}\left(\pi-C_{5}H_{5}\right)_{2}\right]^{0} $ is
- AMUEEE - 2018
- coordination compounds
Concepts Used:
Bohr's Model of Hydrogen Atom
Niels Bohr introduced the atomic Hydrogen model in 1913. He described it as a positively charged nucleus, comprised of protons and neutrons, surrounded by a negatively charged electron cloud. In the model, electrons orbit the nucleus in atomic shells. The atom is held together by electrostatic forces between the positive nucleus and negative surroundings.
Read More: Bohr's Model of Hydrogen Atom
Bohr's Theory of Hydrogen Atom and Hydrogen-like Atoms
A hydrogen-like atom consists of a tiny positively-charged nucleus and an electron revolving around the nucleus in a stable circular orbit.
Bohr's Radius:
If 'e,' 'm,' and 'v' be the charge, mass, and velocity of the electron respectively, 'r' be the radius of the orbit, and Z be the atomic number, the equation for the radii of the permitted orbits is given by r = n2 ｘr1, where 'n' is the principal quantum number, and r1 is the least allowed radius for a hydrogen atom, known as Bohr's radius having a value of 0.53 Å.
Limitations of the Bohr Model
The Bohr Model was an important step in the development of atomic theory. However, it has several limitations.
- Bohr’s model of the atom failed to explain the Zeeman Effect (effect of magnetic field on the spectra of atoms).
- It failed to explain the Stark effect (effect of electric field on the spectra of atoms).
- The spectra obtained from larger atoms weren’t explained.
- It violates the Heisenberg Uncertainty Principle.