Which of the following refining methods works on the principle that impurities are more soluble in the melt than in the solid state of the metal?
[A] Liquation
[B] Electrolytic refining
[C] Zone refining
[D] Vapour Phase refining

What is the total number of allowed orbitals in a shell, if principal quantum number is n?
[A] n
[B] 2n
[C] n²
[D] n³

What can be the maximum number of electrons in a shell, if principal quantum number is n?
[A] n
[B] n²
[C] 2n²
[D] 3n³

Which of the following quantum number determines the number of sub-shells?
[A] Electron spin quantum number
[B] Principal quantum number
[C] Magnetic quantum number
[D] Azimuthal quantum number

What do we call an ideal body which emits and absorbs all frequencies?
[A] Black body
[B] White body
[C] Red body
[D] Zero body

Which of these species are isoelectronic?
[A] Al⁺ , B^–
[B] Mg⁺ , Cu^–
[C] Na⁺ , Al^–
[D] Na⁺ , F^–

Which of the following are the limitations of Bohr’s model of atom?
[A] it cannot explain spectrum of atoms containing more than one electron
[B] it cannot explain the Zeeman effect
[C] it cannot explain the Stark effect
[D] All of the above

What is the general Q-value for alpha-decay?
[A] greater than 0
[B] less than 0
[C] equal to 0
[D] None of the above

When is the gamma ray emitted?
[A] When a nucleus in a ground state goes to the excited state
[B] When a nucleus in an excited state spontaneously decays to its ground state
[C] When alpha rays and beta rays collide
[D] None of the above

Which of the following is correct about the principal quantum number?
[A] It determines the size of the orbital
[B] It can have positive integer values
[C] It identifies the shell
[D] All of the above

What is the total number of allowed orbitals in a shell, if principal quantum number is n?
[A] n
[B] 2n
[C] n²
[D] n³