General
✓✗A photon of frequency ν has momentum
- hνc
- h/ν
- hν/c
- c/hν
General
✓✗The maximum number of electrons in an atom with the quantum numbers n = 3 and ml = 0 is
- 18
- 6
- 2
- 10
General
✓✗The energy of a photon is 3.0 × 10−19 J. Its wavelength is about (h = 6.626 × 10−34 J s, c = 3 × 108 m s−1)
- 1326 nm
- 331 nm
- 66.3 nm
- 663 nm
General
✓✗If the kinetic energy of an electron is increased four times, its de Broglie wavelength becomes
- one-fourth
- four times
- half
- double
General
✓✗The de Broglie wavelength of an electron moving with a velocity of 1 × 106 m s−1 is about (h = 6.626 × 10−34 J s, me = 9.1 × 10−31 kg)
- 0.073 nm
- 73 nm
- 7.3 nm
- 0.73 nm
General
✓✗Which of the following orbitals does NOT exist?
- 5p
- 4f
- 3d
- 2d
General
✓✗The energy of the electron in the ground state of the hydrogen atom is
- −13.6 eV
- +13.6 eV
- −3.4 eV
- zero
General
✓✗Assertion: The de Broglie wavelength of an electron in a Bohr orbit fits a whole number of times around the orbit.
Reason: This condition is equivalent to Bohr's quantisation of angular momentum.
Reason: This condition is equivalent to Bohr's quantisation of angular momentum.
- Both Assertion and Reason are true and Reason is the correct explanation of Assertion
- Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
- Assertion is true but Reason is false
- Both Assertion and Reason are false
General
✓✗The uncertainty principle rules out the concept of
- energy levels
- quantum numbers
- the nucleus
- definite orbits for electrons
General
✓✗If the radius of the first Bohr orbit of hydrogen is x, the radius of the third orbit of Li2+ is
- 9x
- x/3
- 3x
- x
General
✓✗Which of the following statements about the 1s and 2s orbitals of hydrogen is correct?
- 1s has a node at the nucleus
- Both are spherical, but 2s has one radial node
- Both have one radial node
- 2s is smaller than 1s
General
✓✗Which orbital is degenerate with 3s in the hydrogen atom?
- 2p
- 4s
- 3d
- 2s
General
✓✗The size of an s orbital increases as
- m increases
- spin changes
- l increases
- n increases
General
✓✗If the uncertainties in position and in velocity of a particle of mass m are equal, the minimum value of each is
- \( \sqrt{\dfrac{h}{4\pi m}} \)
- \( \sqrt{\dfrac{h}{2\pi m}} \)
- \( \sqrt{\dfrac{hm}{4\pi}} \)
- \( \dfrac{h}{4\pi m} \)
General
✓✗If the uncertainty in the position of an electron is halved, the minimum uncertainty in its momentum
- becomes four times
- remains the same
- is halved
- doubles