In Bohr's model if the atomic radius of the first orbit is r0, then what will be the radius of the third orbit?
1.
2.
3.
4.
What is the ratio of the speed of an electron in the first orbit of an H-atom to the speed of light?
1.
2. 137
3.
4.
The total energy of an electron in the first excited state of a hydrogen atom is about –3.4 eV. Its kinetic energy in this state will be:
1. –6.8 eV
2. 3.4 eV
3. 6.8 eV
4. –3.4 eV
In the nth orbit, the energy of an electron is \(\mathrm{E}_{\mathrm{n}}=-\frac{13.6}{\mathrm{n}^2} \mathrm{~eV}\) for the hydrogen atom. What will be the energy required to take the electron from the first orbit to the second orbit?
1. 10.2 eV
2. 12.1 eV
3. 13.6 eV
4. 3.4 eV
If an electron in a hydrogen atom jumps from the 3rd orbit to the 2nd orbit, it emits a photon of wavelength . What will be the corresponding wavelength of the photon when it jumps from the 4th orbit to the 3rd orbit?
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Hydrogen 1H1, Deuterium 1H2, singly ionised helium (2He4)+, and doubly ionised lithium (3Li6)++ all have one electron around the nucleus. Consider an electron transition from n = 2 to n = 1. If the wavelengths of emitted radiations are λ1 ,λ2 ,λ3 and λ4 respectively, then approximately which one of the following is correct?
1. | \(4 \lambda_1=2 \lambda_2=2 \lambda_3=\lambda_4\) |
2. | \( \lambda_1=2 \lambda_2=2 \lambda_3=\lambda_4\) |
3. | \( \lambda_1=\lambda_2=4 \lambda_3=9\lambda_4\) |
4. | \( \lambda_1=2\lambda_2=3 \lambda_3=\lambda_4\) |
Statement I: | \(n^\text{th}\) Bohr orbit in an atom is directly proportional to \(n^3.\) | The time period of revolution of an electron in its
Statement II: | \(n^\text{th}\) Bohr orbit in an atom is directly proportional to \(n.\) | The K.E. of an electron in its
1. | Statement I is incorrect and Statement II is correct. |
2. | Both Statement I and Statement II are correct. |
3. | Both Statement I and Statement II are incorrect. |
4. | Statement I is correct and Statement II is incorrect. |
The radius of a hydrogen atom in its ground state is 5.3×10-11 m. After collision with an electron, it is found to have a radius of 21.2 ×10-11 m. What is the principal quantum number n of the final state of the atom?
1. n = 4
2. n = 2
3. n = 16
4. n = 3
What is the ratio of the circumference of the first Bohr orbit for the electron in the hydrogen atom to the de-Broglie wavelength of electrons having the same velocity as the electron in the first Bohr orbit of the hydrogen atom?
1. 1:1
2. 1:2
3. 1:4
4. 2:1
Considering the 3rd orbit of He+ (Helium ion), using the non-relativistic approach, the speed of the electron in this orbit will be: (Given: Z=2, K=9x109, and Planck's constant, h=6.6x10-34 J-s)
1. 2.92x108 m/s
2. 1.46x m/s
3. 0.73x108 m/s
4. 3.0x108 m/s