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

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

Which orbital will have lower energy if two orbitals have the same value of (n+l)?
[A] orbital with lower value of n
[B] orbital with lower value of l
[C] orbital with lower value of (n-l)
[D] None of the above

Which of the following substance was used as a moderator in CIRUS reactor?
[A] Heavy water
[B] water
[C] solid graphite
[D] No moderator was used

What do we call the reactions in which heat is generated?
[A] Exothermic
[B] Endothermic
[C] Both a and b
[D] None

Which of the following reactions take place when iron nail in a copper sulphate solution becomes brownish in colour?
[A] Decomposition reaction
[B] Displacement reaction
[C] Double Displacement reaction
[D] None of the above