A glow worm of mass 5.0 g emits red light (650 nm) with a power of 0.1 W. entirely in the backward direction. What velocity would it accelerate to after 10 years, if released in free space (and assumed to be alive)?
1. 9.14 ms-1
2. 28.08 ms-1
3. 11.05 ms-1
4. 21.04 ms-1
Which of the following postulates does not belong to Bohr's model of the atom?
1. Angular momentum is an integral multiple of h/2
2. The electron stationed in the orbit is stable
3. The path of an electron is circular
4. The change in the energy levels of electron is continuous
The total number of orbitals having l = 3 is -
1. 3
2. 7
3. 5
4. 9
Bohr's atomic model provides explanations for:
1. | The spectrum of hydrogen atoms only.
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2. | The spectrum of an atom or ion containing only one electron.
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3. | The spectrum of hydrogen molecule.
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4. | The solar spectrum. |
The presence of one electron each in the three 2p sub-shell of nitrogen is explained by
1. Uncertainty principle
2. Hund's rule
3. Pauli's principle
4. Bohr's theory
When the atoms of gold sheet are bombarded with a beam of -particles, only a few a-particles get deflected where as most of them go straight undeflected. This is because:
1. | The force of attraction on the -particles by the oppositely charged electron is not sufficient. |
2. | The nucleus occupies much smaller volume as compared to the volume of atom. |
3. | The force of repulsion on fast moving -particles is very small. |
4. | The neutrons in the nucleus do not have any effect on -particles. |
Using radiation of wavelength 3500 Å, it is observed that the maximum kinetic energy of the emitted photoelectrons is 1.6 eV for potassium. Calculate the work function of the metal. [h=6.626 x 10-34 Js, 1 eV=1.6 x 10-19 J]
1. 3 eV
2. 2.5 eV
3. 3.5 eV
4. 2 eV
To give designation to an orbital, we need
1. Principal and azimuthal quantum number
2. Principal and magnetic quantum number
3. Azimuthal and magnetic quantum number
4. Principal, azimuthal and magnetic quantum numbers.
The rest mass of a proton is 1.673 x 10-27 kg and that of the electron is 9.109 x 10-31 kg. What must be the speed of the proton which has the same de Broglie wavelength as an electron moving with a speed of 9 x 106 m/s?
1. 3600 m/s
2. 4900 m/s
3. 4300 m/s
4. 5600 m/s
Which one of the following statement is not true about the quantum numbers n, l, m and s
1. m gives the information on the energy of the electron in a given orbital.
2. l gives an idea of the shape of the orbital.
3. n gives information on the size of the orbit.
4. s gives the direction of spin of the electron in the orbital.