The electronic transitions from n = 2 to n= 1 will produce shortest wavelength in (where n = principal quantum state)

• Li²⁺ 

• He⁺

• H

• H⁺

In the following electron-dot structure, calculate the formal charge from left to right nitrogen atom; 

• -1, -1, +1

• -1, +1, -1

• +1, -1, -1

• +1, -1, +1

A radioactive atom ${}_{\mathrm{Y}}{}^{\mathrm{X}}$M emits two a particles and one B particle successively. The number of neutrons in the nucleus of the product will be

• X - 4 - Y

• X - Y - 5

• X - Y - 3

• X - Y - 6

For a particular value of azimuthal quantum number, the total number of magnetic quantum number values are given by

• l = $\frac{\mathrm{m} + 1}{2}$

• l = $\frac{\mathrm{m} - 1}{2}$

• l = $\frac{2\mathrm{m} + 1}{2}$

• m = $\frac{2\mathrm{l} + 1}{2}$

What is the wavelength of an α-particle having mass 6.6 × 10^-27 kg moving with a speed of 10⁵ cms^-1? ( h = 6.6 × 10^-34 kgm² - s)?

• 2 × 10^-12 m

• 3 × 10^-10 m

• 1 × 10^-10 m

• 2 × 10^-10 m

46.

With what velocity should an $\mathrm{\alpha }$-particle travel towards the nucleus of a copper atom to arrive at a distance of 10^-13m from the nucleus of the copper atom?(K = 9x 10⁹ Nm²/C² (Mass of $\mathrm{\alpha }$-particle = 6.64 x 10^-27kg).

• 634 x 10⁶ ms^-1

• 634 x10⁵ ms^-1

• 5.34 x 10⁶ ms^-1

• 534 x 10⁵ ms^-1

What is the ratio of the velocities of CH₄ and O₂ molecules so that they are associated with de-Broglie waves of equal wavelengths?

• 1:2

• 2: 1

• 3: 2

• 1: 2

What is the value of the spin quantum number of the last electron ford d⁹ -configuration ?

• 0

• $-\frac{1}{2}$

• $\frac{1}{2}$

• 1

The ratio of slopes of K_max vs V and V₀ vs v curves in the photoelectric effects gives (v = frequency, K_max = maximum kinetic energy, v₀ = stopping potential)

• the ratio of Planck's constant of electronic charge

• work function

• Planck's constant

• charge of electron

According to Bohr's theory, the angular momentum for an electron of 3rd orbit is

• 3h

• 1.5h

• 9h

• $2\frac{\mathrm{h}}{\mathrm{\pi }}$