In a Geiger-Marsden experiment, what is the distance of the closest approach to the nucleus of a 7.7 MeV α-particle before it comes momentarily to rest and reverses its direction?
1. 10 fm
2. 25 fm
3. 30 fm
4. 35 fm
It is found experimentally that 13.6 eV energy is required to separate a hydrogen atom into a proton and an electron. The velocity of the electron in a hydrogen atom is:
1. 3.2×106 m/s
2. 2.2×106 m/s
3. 3.2×106 m/s
4. 1.2×106 m/s
Statement I: | nth Bohr orbit in an atom is directly proportional to n3. | The time period of revolution of an electron in its
Statement II: | nth 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. |
According to the classical electromagnetic theory, the initial frequency of the light emitted by the electron revolving around a proton in the hydrogen atom is: (The velocity of the electron moving around a proton in a hydrogen atom is 2.2×106 m/s)
1. | 7.6×1013 Hz | 2. | 4.7×1015 Hz |
3. | 6.6×1015 Hz | 4. | 5.2×1013 Hz |
1. | n1=6 and n2=2 |
2. | n1=8 and n2=1 |
3. | n1=8 and n2=2 |
4. | n1=4 and n2=2 |
A 10 kg satellite circles earth once every 2 h in an orbit having a radius of 8000 km. Assuming that Bohr’s angular momentum postulate applies to satellites just as it does to an electron in the hydrogen atom. The quantum number of the orbit of the satellite is:
1. 2.0×1043
2. 4.7×1045
3. 3.0×1043
4. 5.3×1045
The minimum orbital angular momentum of the electron in a hydrogen atom is:
1. h
2. h/2
3. h/2π
4. h/λ
Let L1 and L2 be the orbital angular momentum of an electron in the first and second excited states of the hydrogen atom, respectively. According to Bohr's model, the ratio L1:L2 is:
1. 1:2
2. 2:1
3. 3:2
4. 2:3