CBSE
Multiple Choice QuestionsMaximum energy is evolved during which of the following transitions?
n = 1 to n= 2
n = 2 to n= 6
n = 2 to n= 1
n = 6 to n= 2
If the radius of the first Bohr orbit of the hydrogen atom is 5.29 x 10' m, the radius of the second orbit will be
21.16 x 10−11 m
15.87 x 10−11 m
10.58 x 10−11 m
2.64 x 10−11 m
If the binding energy of the electron in a hydrogen atom is 13.6 eV, the energy required to remove the electron from the first excited state of Li2+ is
30.6 eV
13.6 eV
3.4 eV
122.4 eV
If λ1 and λ2 are the wavelengths of the first members of the Lyman and Paschen series respectively, then λ1 : λ2 is
1 : 3
1 : 30
7 : 50
7 : 108
The ground state energy of H-atom is 13.6 eV. The energy needed to ionize H-atom from its second excited state is
1.51 eV
3.4 eV
13.6 eV
12.1 eV
Which of the following is more close to a black body?
Black board paint
Green leaves
Black holes
Red roses
Continuous emission spectrum, emitted wavelength about spectrum, the range depends upon:
temperature of the source
material of the source
surface area of the source
all of the above
If the temperature of a black body is doubled, the wavelength at which the spectral radiancy has its maximum, is
doubled
halved
quadrupled
unchanged
Electrons in a certain energy level n = n1 can emit 3 spectral lines. When they are in another energy level, n=n2 they can emit 6 spectral lines. The orbital speed of the electrons in the orbits are in the ratio
4 : 3
3 : 4
2 : 1
1 : 2
Assertion: Bohr had to postulate that the electrons in stationary orbits around the nucleus do not radiate.
Reason: According to classical physics all moving electrons radiate.
if both assertion and reason are true and the reason is the correct explanation of the assertion
if both assertion and reason are true and the reason is not the correct explanation of the assertion
if assertion is true but reason is false
if both assertion and reason are false statements
