The energy of an electron is the 3S orbital ( excited state) of H- atom is

• -1.5 eV

• -13.6 eV

• -3.4 eV

• -4.53 eV

In the hydrogen atom spectrum, the emission of the least energetic photon takes place during the transition from n = 6 energy level to n = .......... energy level.

• 1

• 3

• 5

• 4

The threshold frequency of a metal corresponds to the wavelength of x nm. In two separate experiments A and B, incident radiations of wavelengths 1/2x nm and 1/4x nm respectively are used. The ratio of kinetic energy of the released electrons in experiment 'B' to that in experiment 'A' is

• 1/3

• 2

• 4

• 3

The minimum values of uncertainties involved in the determination of both the position and velocity of a particle respectively are 1 × 10^-10 m and 1 × 10^-10 ms^-1.Then, the mass (in kg) of the particle is

• 5.270 × 10^-15

• 5.270 × 10^-20

• 5.270 × 10^-16

• 5.270 × 10^-10

The number of electrons with azimuthal quantum number l = 1 and l = 2 for Cr in ground state respectively are

• 12, 5

• 12, 4

• 16, 5

• 16, 4

In which one of the following, d-d transition involves absorption in the ultraviolet region?

• [Cu(H₂O)₄]²⁺

• [Ti(H₂O)₆]³⁺

• [Co(NH₃)₆]³⁺

• [Co(CN)₆]^3-

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

• 1002.7 Å

• 1215.67 Å

• 1127.30 Å

• 911.7 Å

Which of the following are isoelectronic species?

(i) NH₃

(ii) CH${}_3^{+}$

(iii) NH${}_2^{-}$

(iv) NH${}_4^{+}$

Choose the correct answer from the codes given below.

• (i), (ii), (iii)

• (ii), (iii), (iv)

• (i), (ii), (iv)

• (i), (iii), (iv)

339.

The ratio of the frequency corresponding to the third line in Lyman series of hydrogen atomic spectrum to that of the first line in Balmer series of Li²⁺ spectrum is

• $\frac{4}{5}$

• $\frac{5}{4}$

• $\frac{4}{3}$

• $\frac{3}{4}$

Which transition in the hydrogen atomic spectrum will have the same wavelength as the transition will have the same wavelength, n = 4 to n = 2 of He⁺ spectrum?

• n = 4 to n = 3

• n = 2 to n = 1

• n = 4 to n = 2

• n = 3 to n = 1