81.

The shortest wavelength in hydrogen spectrum of Lyman series when R_H = 109678 cm^-1 is

• 1002.7 Å

• 1215.67 Å

• 1127.30 Å

• 911.7 Å

The electrons, identified by quantum numbers n and l,

(I) n = 3; l = 2; (II) n = 5; l = 0; (III) n = 4; l = 1; (IV) n = 4; l = 2; (V) n = 4; l = 0;

can be placed in order of increasing energy as-

• I < V < III < IV < II

• I < V < III < II < IV

• V < I < III < II < IV

• V < I < II < III < IV

The number of photons emitted per second by a 60 W source of monochromatic light of wavelength 663 nm is (h = 6 .63 × 10^-34 Js)

• 4 × 10^-20

• 1.5 × 10²⁰

• 3 × 10^-20

• 2 × 10²⁰

Energy released, when one atom of uranium undergoes nuclear fission according to the following reaction is (atomic mass of U = 235.060; n = 1.009; Ba= 143.881 and Kr = 89.94 7) about 

₉₂U²³⁵ + ₀n¹ → ₅₆Ba¹⁴⁴ + ₃₆Kr⁹⁰ + 2 ₀n¹

• 235 MeV

• 208 MeV

• 931.5 MeV

• 5.33 x 10²³ MeV

Identify the nuclear reaction that differs from the rest.

• γ- decay

• κ- capture

• Positron emission

• β-decay

Which diagram best represents the appearance of the line spectrum of atomic hydrogen in the visible region?

The correct set of quantum numbers (n, l and m respectively) for the unpaired electron of chlorine atom is :

• 2, 1, 0

• 2, 1, 1

• 3, 1, 1

• 3, 2, 1

The relationship between the energy E₁ of the radiation with a wavelength 8000 Å and the energy E₂ of the radiation with a wavelength Å 16000  is:

• E₁ = 6E₂

• E₁ = 2E₂

• E₁ = 4E₂

• E₁ = 4E₂

Calculate the mass loss in the following.

${}_1{}^2\mathrm{H} + {}_1{}^3\mathrm{H} \to {}_2{}^4\mathrm{H} + {}_0{}^1\mathrm{n}$

[Given the masses : ²H = 2.014;³H = 3.016; He = 4.004; n = 1.008 amu]  

• 0.018 amu

• 0.18 amu

• 0.0018 amu

• 1.8 amu

The observation that the ground state of nitrogen atom has 3 unpaired electrons in its electronic configuration and not otherwise is associated with:

• Pauli's exclusion principle

• Hund's rule of maximum multiplicity

• Heisenberg's uncertainty relation

• Ritz combination principle