What is X in the following reaction ?

₁₂Mg²⁶ + ₁H² → ₁₂Mg²⁷ + X

• γ-ray

• ₀n¹

• ₁H¹

• ₁D²

Which one of the following statements is not correct?

• Rydberg's constant and wave number have same units

• Lyman series of hydrogen spectrum occurs in the ultraviolet region

• The angular momentum of the electron in the ground state hydrogen atom is equal to $\frac{\mathrm{h}}{2\mathrm{\pi }}$

• The radius of first Bohr orbit of hydrogen atom is 2.116 × 10^-8 cm.

The energy of an electromagnetic radiation is 19.875 × 10^-13 ergs. What is its wave number in cm^-1? (h = 6.625 × 10^-27 erg sec; c = 3 × 10¹⁰ cm sec^-1)

• 1000

• 10⁶

• 100

• 10000

If the wavelength of an electromagnetic radiation is 2000 Å, what is its energy in ergs?

• 9.94 × 10^-12

• 9.94 × 10^-19

• 4.97 × 10^-12

• 4.97 × 10^-19

Which one of the following statements is correct?

• The radius (R) of a nuclide of mass number A is given by the equation R = R₀(A)^1/2 (R₀ = constant)

• ₇N¹⁵ and ₈O¹⁶ are isobars

• The end product nuclide in thorium (4n) series is ₈₃Bi²⁰⁹

• ₂₀Ca⁴⁰ has magic number of protons and magic number of neutrons

₆C¹² and ₁T³ are formed in nature due to the nuclear reaction of neutron with

• ₇N¹⁴

• ₆C¹³

• ₂He⁴

• ₃Li⁶

The atomic numbers of elements X,Y and Z are 19, 21 and 25 respectively. The number of electrons present in the M-shell of these elements follow the order

• Z > X > Y

• X > Y > Z

• Z > Y > X

• Y > Z > X

Which of the following elements has least number of electrons in its M shell ?

• K

• Mn

• Ni

• Sc

369.

An electron is moving in Bohr's fourth orbit. Its de-Broglie wave length is λ. What is the circumference of the fourth orbit ?

• 2/λ

• 2λ

• 4λ

• 4/λ

Which of the following is correct?

• ₁H¹ and ₂He³ are isotopes

• ₆C¹⁴ and ₇N¹⁴ are isotopes

• ₁₉K³⁹ and ₂₀Ca⁴⁰ are isotones

• ₉F¹⁹ and ₁₁Na²⁴ are isodiaphers