121.

For a crystal, the angle of diffraction (2 θ) is 90° and the second order line has a d value of 2.28 Å. The wavelength (in Å) of X-rays used for Bragg's diffraction is

• 1.612

• 2.00

• 2.28

• 4.00

The wavelength of a spectral line emitted by hydrogen atom in the Lyman series is $\frac{16}{15\mathrm{R}} \mathrm{cm}$. What is the value of n₂? ( R= Rydberg constant).

• 2

• 3

• 4

• 1

The maximum number of sub-levels, orbitals and electrons in N shell of an atom are respectively

• 4, 12, 32

• 4, 16, 30

• 4, 16, 32

• 4, 32, 64

The wavelengths of electron waves in two orbits is 3 : 5. The ratio of kinetic energy of electrons will be 

• 25 : 9

• 5 : 3

• 9 : 25

• 3 : 5

Which one of the following transitions of an electron in hydrogen atom emits radiation of the lowest wavelength?

• n₂ = ∞ to n₁=2

• n₂= 4 to n₁ =3

• n₂= 2 to n₁ =1

• n₂ = 5 to n₁=3

Which one of the following conditions is incorrect for a well behaved wave function (Ψ)?

• Ψ must be fine

• Ψ must be single valued

• Ψ must be infinite

• Ψ must be continuous

The electron affinity values of elements A, B, C and D are respectively -135, -60, -200 and -348 kJ mol^-1. The outer electronic configuration of element B is

• 3s² 3p⁵

• 3s² 3p⁴

• 3s² 3p³

• 3s² 3p²

Which one of the following frequencies of radiation (in Hz) has a wavelength of 600 nm?

• 2.0 × 10¹³ 

• 5.0 × 10¹⁶ 

• 2.0 × 10¹⁴ 

• 5.0 × 10¹⁴ 

According to Bohr's theory which one of the following values of angular momentum of hydrogen atom is not permitted?

• $\frac{1.25 \mathrm{h}}{\mathrm{\pi }}$

• $\frac{\mathrm{h}}{\mathrm{\pi }}$

• $\frac{1.5 \mathrm{h}}{\mathrm{\pi }}$

• $\frac{0.5 \mathrm{h}}{\mathrm{\pi }}$

The number of radial nodes of 3s and 2p orbitals respectively are

• 0, 2

• 2, 0

• 1, 2

• 2, 1