General
✓✗The number of photons of light of wavelength 500 nm that together carry 1 J of energy is about (h = 6.626 × 10−34 J s, c = 3 × 108 m s−1)
- 2.5 × 1018
- 2.5 × 1015
- 1.0 × 1019
- 4.0 × 10−19
General
✓✗The size of an s orbital increases as
- m increases
- spin changes
- l increases
- n increases
General
✓✗For which of the following sets of four quantum numbers will an electron have the highest energy?
- n = 4, l = 1, m = 0, s = −1/2
- n = 5, l = 0, m = 0, s = −1/2
- n = 3, l = 2, m = 1, s = +1/2
- n = 4, l = 2, m = −1, s = +1/2
General
✓✗Which of the following has the highest frequency?
- Radio waves
- Red light
- Violet light
- Infrared radiation
General
✓✗Assertion: The energy of radiation is emitted or absorbed only in discrete amounts.
Reason: The intensity of radiation is proportional to its frequency.
Reason: The intensity of radiation is proportional to its frequency.
- 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 radius of the hydrogen atom in the ground state is 0.53 Å. The radius of the Li2+ ion (atomic number 3) in a similar state is
- 1.06 Å
- 0.17 Å
- 0.265 Å
- 0.53 Å
General
✓✗In Bohr's model, the time period of revolution of the electron is proportional to
- n/Z
- n2/Z
- n3/Z2
- Z2/n3
General
✓✗Be2+ is isoelectronic with which of the following ions?
- Mg2+
- Na+
- Li+
- H+
General
✓✗The Brackett series of the hydrogen spectrum lies in the
- X-ray region
- infrared region
- visible region
- ultraviolet region
General
✓✗According to the Bohr theory, which of the following transitions in the hydrogen atom will give rise to the least energetic photon?
- n = 6 to n = 5
- n = 5 to n = 3
- n = 5 to n = 4
- n = 6 to n = 1
General
✓✗The 4d, 5p, 5f and 6p orbitals are arranged in the order of decreasing energy. The correct option is
- 6p > 5f > 5p > 4d
- 6p > 5f > 4d > 5p
- 5f > 6p > 4d > 5p
- 5f > 6p > 5p > 4d
General
✓✗A proton and an alpha particle are accelerated through the same potential difference. The ratio of their de Broglie wavelengths (λp : λα) is
- 2 : 1
- 1 : \( 2\sqrt2 \)
- \( 2\sqrt2 \) : 1
- 1 : 1
General
✓✗The frequency of a photon of energy 2.5 × 10−19 J is (h = 6.626 × 10−34 J s)
- 2.65 × 10−15 s−1
- 3.77 × 1014 s−1
- 3.77 × 1015 s−1
- 1.66 × 1014 s−1
General
✓✗Statement I: The magnetic quantum number can take 2l + 1 values.
Statement II: The spin quantum number depends on the value of l.
Statement II: The spin quantum number depends on the value of l.
- Both Statement I and Statement II are correct
- Both Statement I and Statement II are incorrect
- Statement I is correct but Statement II is incorrect
- Statement I is incorrect but Statement II is correct
General
✓✗Statement I: The threshold frequency is characteristic of the metal.
Statement II: Below the threshold frequency, increasing the intensity of light will eject electrons.
Statement II: Below the threshold frequency, increasing the intensity of light will eject electrons.
- Both Statement I and Statement II are correct
- Both Statement I and Statement II are incorrect
- Statement I is correct but Statement II is incorrect
- Statement I is incorrect but Statement II is correct