CBSE
Multiple Choice QuestionsAssertion: Total energy of electron in an hydrogen atom is negative.
Reason: It is bounded to the nucleus.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
Ratio of longest wavelengths corresponding to Lyman and Balmer series in hydrogen spectrum is
The current gain for a transistor working as common-base amplifier is 0.96. If the emitter current is 7.2 mA, then base current is
0.35 mA
0.28 mA
0.39 ma
0.43 mA
Ionisation potential of hydrogen atom is 13.6 V. Hydrogen atoms in the ground state are excited by monochromatic radiation of photon energy 12.1 eV. The spectral lines emitted by hydrogen atoms according to Bohr's theory will be
one
two
four
three
A triply ionized beryllium ( Be3+ ) has the same orbital radius as the ground state of hydrogen. Then the quantum state n of Be3+ is
n = 1
n = 2
n = 3
n = 4
Assertion: Electrons in the atom are held due to Coulomb forces.
Reason: The atom is stable only because the centripetal force due to Coulomb's law is balanced by the centrifugal force.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
If the wavelength of 1line of Balmer series of hydrogen is 6561 A, the wavelength of the 2 line of series will be
9780 Ao
4860 Ao
8857 Ao
4429 Ao
Assertion: Bohr's atomic model cannot be used to explain multiple electron species.
Reason: It does not take inter-electronic interactions in account.
If both assertion and reason are true and reason
is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
Total energy of an electron in hydrogen atoms above 0 eV leads to
ionisation of the atom
accelerate the atom
send the atom in higher excited state
none of these
Total energy of the electron in hydrogen atom above 0 eV leads to
continuation of energy states
large number of discrete ionised states
balmer series
paschen series
