371.

What is the correct order of spin only magnetic moment (in BM) of Mn²⁺, Cr²⁺ and V²⁺ ?

• Mn²⁺ > V²⁺ > Cr²⁺

• V²⁺ > Cr²⁺ > Mn²⁺

• Mn²⁺ > Cr²⁺ > V²⁺

• Cr²⁺ > V²⁺ > Mn²⁺ 

The uncertainties in the velocities of two particles A and B are 0.05 and 0.02 m/s^-1 respectively. The mass of B is five times to that of mass A. What is the ratio of uncertainities $\left(\frac{∆{\mathrm{x}}_{\mathrm{A}}}{∆{\mathrm{x}}_{\mathrm{B}}}\right)$ in their positions?

• 2

• 0.25

• 4

• 1

The energy of a photon is 3 × 10^-12 ergs. What is its wavelength in nm ?

(h = 6.62 × 10^-27 ergs ; c = 3 × 10¹⁰ cm/s)

• 662

• 1324

• 66.2

• 6.62

Which of the following is not correct ?

• Nuclei of atoms participate in nuclear reactions

• ₂₀Ca⁴⁰ and ₁₈Ar⁴⁰ are isotones

• 1 amu of mass defect is approximately equal to 931.5 MeV.

• Uranium (U²³⁸) series is known as (4n + 2) series.

An electronic transition in hydrogen atom results in the formation of H_α line of hydrogen in Lyman series, the energies associated with the electron in each of the orbits involved in the transition (in kcal mol^-1) are 

• -313,6, - 34.84

• -313.6, - 78.4

• -78.4,- 34.84

• -78.4,-19.6

The velocities of two particles A and B are 0.05 and 0.02 ms^-1 respectively. The mass of B is five times the mass of A. The ratio of their de-Broglie's wavelength is

• 2 : 1

• 1 : 4

• 1 : 1

• 4 : 1

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