31. Choose the correct order of these elements in terms of abundance in the earth’s crust:
[A] Iron > Silicon > Oxygen >Aluminium
[B] Oxygen > Silicon > Aluminium > Iron
[C] Oxygen> Iron > Aluminium > Silicon
[D] Iron > Aluminium > Silicon > Oxygen
Show Answer
Correct Answer: B [Oxygen > Silicon > Aluminium > Iron]
Notes:
Oxygen is the most abundant element in the earth’s crust followed by Silicon, Aluminium and Iron. It comprises almost half of the mass of the earth’s crust.
32. Choose the incorrect ‘Metal -ore’ pair:
[A] Iron – Magnetite
[B] Aluminium – Bauxite
[C] Gold – Calaverite
[D] Calcium – Carnalite
Show Answer
Correct Answer: D [Calcium – Carnalite]
Notes:
Carnalite is an ore of Potassium. It’s a hydrated potassium magnesium chloride. The chemical formula of Carnalite is KCl. MgCl2 . 6H2O.
33. Which of the following minerals contain mercury?
[A] Cinnabar
[B] Corderoite
[C] Livingstonite
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
Cinnabar is a mercury sulfide (HgS) mineral. Corderoite is mercury sulfide chloride mineral and is very rare. Livingstonite is a mercury antimony sulfosalt mineral.
34. Choose the correct statement about Hydraulic Washing:
[A] It is used for concentration of ores
[B] It is based on differences in magnetic properties of the ore components
[C] Both a and b
[D] None of the above
Show Answer
Correct Answer: A [It is used for concentration of ores]
Notes:
Hydraulic Washing is a method used for concentration of ores. It is a type of gravity separation as it is based on the differences in gravities of the ore and the gangue particles.
35. Which of the following is correct about Roasting?
[A] the ore is heated in a regular supply of air
[B] It is used to convert the concentrated ore to oxide
[C] it is commonly used for suiphide ores
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
Roasting is the process of converting an ore into its oxide by heating the ore in regular supply of oxygen. It is commonly used for suiphide ores.
36. What is the relation between mass and wavelength of any matter, as per de Broglie’s relation?
[A] Both are directly proportional
[B] Both are inversely proportional
[C] Both are independent of each other
[D] wavelength is twice the square of the mass
Show Answer
Correct Answer: B [Both are inversely proportional]
Notes:
According to de Broglie, every object in motion has a wave character. As per de Broglie’s relation, mass and wavelength are inversely proportional to each other.
37. Which of the following characteristic of an electron is impossible to determine simultaneously, as per Heisenberg’s Uncertainty Principle?
[A] exact charge and exact velocity
[B] exact charge and exact mass
[C] exact position and exact momentum
[D] exact mass and exact position
Show Answer
Correct Answer: C [exact position and exact momentum]
Notes:
The Heisenberg’s Uncertainty Principle states that it is impossible to determine simultaneously, the exact position and exact momentum (or velocity) of an electron.
38. Which of the following statements related to principal quantum number (n) is not correct?
[A] Energy of the orbital increases with increase of n
[B] Size of an orbital increases with increase of n
[C] The shell M is represented by principal quantum number 2
[D] Total number of allowed orbitals in Shell K is 1
Show Answer
Correct Answer: C [The shell M is represented by principal quantum number 2]
Notes:
Statement 3 is incorrect. The shell M is represented by principal quantum number 3. Size of an orbital increases with increase of principal quantum number ‘n’. The energy of the orbital also increases with increase of n. Total number of allowed orbitals in Shell K is 1.
39. Which of the following quantum number is also known as orbital angular momentum?
[A] Principal quantum number
[B] Azimuthal quantum number
[C] Magnetic quantum number
[D] Electron spin quantum number
Show Answer
Correct Answer: B [Azimuthal quantum number]
Notes:
Azimuthal quantum number is also known as orbital angular momentum or subsidiary quantum number. It is represented by ‘l’.
40. Which of the following quantum numbers is not necessary to identify an orbital?
[A] Principal quantum number
[B] Azimuthal quantum number
[C] Magnetic quantum number
[D] Electron Spin quantum number
Show Answer
Correct Answer: D [Electron Spin quantum number]
Notes:
An orbital is identified by the set of 3 quantum numbers: Principal quantum number, Azimuthal quantum number and magnetic quantum number.
