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SPSC Subject Specialist practice questions

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Question 1Subject-specific content knowledge

If 3x − 7 = 14, what is the value of x?

  1. 5
  2. 21
  3. 7 Correct answer.
  4. 3

Explanation

Adding 7 to both sides gives 3x = 21, and dividing both sides by 3 gives x = 7. The same operation must be applied to both sides to preserve the equality.

Question 2Subject-specific content knowledge

Which organelle is the principal site of ATP production in a eukaryotic cell?

  1. Golgi apparatus
  2. Ribosome
  3. Lysosome
  4. Mitochondrion Correct answer.

Explanation

Mitochondria carry out oxidative phosphorylation on their inner membrane, generating most of the cell's ATP. The other listed organelles serve protein synthesis, modification and packaging, and intracellular digestion respectively.

Question 3Subject-specific content knowledge

Choose the sentence that is grammatically correct.

  1. Each of the students has submitted the assignment. Correct answer.
  2. Each of the students have submitted the assignment.
  3. Each of the students were submitted the assignment.
  4. Each of the students are submitting the assignment.

Explanation

'Each' is a singular indefinite pronoun, so it takes a singular verb even when it is followed by a plural noun inside a prepositional phrase. The verb agrees with 'each', not with 'students'.

Question 4Subject-specific content knowledge

The chemical symbol for potassium is:

  1. K Correct answer.
  2. P
  3. Na
  4. Po

Explanation

Potassium takes the symbol K from its Latin name kalium, following the rule that symbols may derive from Latin or Greek names. The remaining symbols belong to different elements entirely.

Question 5Subject-specific content knowledge

The SI unit of electric current is the:

  1. volt
  2. ampere Correct answer.
  3. coulomb
  4. ohm

Explanation

The ampere is a base SI unit and is defined by fixing the numerical value of the elementary charge. The other units measure charge, potential difference and resistance.

Question 6Subject-specific content knowledge

The longest river in Pakistan is the:

  1. Indus Correct answer.
  2. Ravi
  3. Jhelum
  4. Chenab

Explanation

The Indus rises in Tibet, runs the length of Gilgit-Baltistan, Khyber Pakhtunkhwa and Sindh, and drains into the Arabian Sea, making it the country's longest river. The other three are its tributaries in the Punjab.

Question 7Subject-specific content knowledge

Which part of the CPU performs arithmetic and logical operations?

  1. Control unit
  2. Arithmetic Logic Unit Correct answer.
  3. Registers
  4. Cache memory

Explanation

The Arithmetic Logic Unit executes operations such as addition, subtraction and Boolean comparisons. The control unit decodes and sequences instructions, while cache and registers are storage resources.

Question 8Subject-specific content knowledge

The word 'abundant' is closest in meaning to:

  1. Fragile
  2. Plentiful Correct answer.
  3. Hidden
  4. Scarce

Explanation

'Abundant' describes something existing in large quantity, so 'plentiful' is the nearest synonym. The other choices describe quantity that is small, something concealed, or something easily broken.

Question 9Subject-specific content knowledge

The area of a circle of radius 7 cm, taking π = 22/7, is:

  1. 44 cm²
  2. 616 cm²
  3. 154 cm² Correct answer.
  4. 308 cm²

Explanation

Area = πr² = (22/7) × 49 = 154 cm². The formula squares the radius, so the radius must be multiplied by itself before multiplying by π.

Question 10Subject-specific content knowledge

A solution has a hydrogen ion concentration of 1 × 10⁻³ mol/dm³. Its pH is:

  1. 3 Correct answer.
  2. 11
  3. 1
  4. −3

Explanation

pH is defined as −log₁₀[H⁺], so −log₁₀(10⁻³) = 3. A value below 7 indicates an acidic solution.

Question 11Subject-specific content knowledge

A car starts from rest and accelerates uniformly at 2 m/s². The distance covered in the first 5 s is:

  1. 5 m
  2. 10 m
  3. 50 m
  4. 25 m Correct answer.

Explanation

Using s = ut + ½at² with u = 0 gives s = ½ × 2 × 5² = 25 m. The time must be squared before multiplying by half the acceleration.

Question 12Subject-specific content knowledge

The enzyme present in human saliva that begins the digestion of starch is:

  1. Salivary amylase Correct answer.
  2. Lipase
  3. Pepsin
  4. Trypsin

Explanation

Salivary amylase, also called ptyalin, hydrolyses starch into maltose in the mouth. Pepsin and trypsin act on proteins, and lipase acts on fats.

Question 13Subject-specific content knowledge

Choose the correct passive form of: 'They will complete the project.'

  1. The project will be completed by them. Correct answer.
  2. The project would be complete by them.
  3. The project is completed by them.
  4. The project will completed by them.

Explanation

The future simple passive is built with will + be + past participle, giving 'will be completed'. The object of the active sentence becomes the subject.

Question 14Subject-specific content knowledge

The Objectives Resolution was adopted by the Constituent Assembly of Pakistan in:

  1. 1950
  2. 1956
  3. 1947
  4. 1949 Correct answer.

Explanation

The Objectives Resolution was passed on 12 March 1949 and set out that sovereignty belongs to Allah and that the state would be governed on Islamic principles. It later became a substantive part of the Constitution.

Question 15Subject-specific content knowledge

The first verses of the Qur'an revealed to the Prophet Muhammad (peace be upon him) belong to Surah:

  1. Al-Muzzammil
  2. Al-Baqarah
  3. Al-Fatihah
  4. Al-Alaq Correct answer.

Explanation

The first five verses of Surah Al-Alaq, beginning with the command to recite, were revealed in the cave of Hira. Surah Al-Fatihah stands first in the compiled text but was not the first to be revealed.

Question 16Subject-specific content knowledge

The binary equivalent of the decimal number 13 is:

  1. 1110
  2. 1101 Correct answer.
  3. 1001
  4. 1011

Explanation

13 = 8 + 4 + 1 = 2³ + 2² + 2⁰, so bits at positions 3, 2 and 0 are set to 1, giving 1101.

Question 17Subject-specific content knowledge

The Bering Strait separates:

  1. Africa from Europe
  2. Europe from North America
  3. Australia from Asia
  4. Asia from North America Correct answer.

Explanation

The Bering Strait lies between the Chukotka Peninsula of Russia and Alaska, connecting the Arctic Ocean with the Bering Sea. It therefore separates the Asian and North American landmasses.

Question 18Subject-specific content knowledge

A 120 m long train moving at 36 km/h passes a pole. The time taken is:

  1. 8 s
  2. 10 s
  3. 12 s Correct answer.
  4. 15 s

Explanation

Convert the speed first: 36 km/h = 10 m/s. When passing a pole the train covers only its own length, so time = 120 ÷ 10 = 12 s.

Question 19Subject-specific content knowledge

Zinc granules are added to dilute hydrochloric acid. The gas evolved is:

  1. Chlorine
  2. Carbon dioxide
  3. Oxygen
  4. Hydrogen Correct answer.

Explanation

The reaction Zn + 2HCl → ZnCl₂ + H₂ shows a reactive metal displacing hydrogen from a dilute acid. The gas burns with a pop when a lighted splint is applied.

Question 20Subject-specific content knowledge

Deficiency of which vitamin causes night blindness?

  1. Vitamin C
  2. Vitamin B12
  3. Vitamin A Correct answer.
  4. Vitamin D

Explanation

Vitamin A is needed to form rhodopsin, the light-sensitive pigment of rod cells, so deficiency impairs dim-light vision. Each of the other vitamins is linked to a different deficiency disease.

Question 21Subject-specific content knowledge

Given log₁₀2 = 0.3010, the value of log₁₀8 is:

  1. 0.3010
  2. 0.6020
  3. 2.4080
  4. 0.9030 Correct answer.

Explanation

Since 8 = 2³, the power rule gives log₁₀8 = 3 log₁₀2 = 3 × 0.3010 = 0.9030.

Question 22Subject-specific content knowledge

The oxidation number of chromium in K₂Cr₂O₇ is:

  1. +7
  2. +6 Correct answer.
  3. +2
  4. +3

Explanation

Taking potassium as +1 and oxygen as −2: 2(+1) + 2x + 7(−2) = 0, so 2x − 12 = 0 and x = +6. The compound is neutral overall, which fixes the chromium value.

Question 23Subject-specific content knowledge

An object is placed 15 cm from a convex lens of focal length 10 cm. The image is formed at:

  1. 10 cm on the other side
  2. 30 cm on the other side Correct answer.
  3. 15 cm on the other side
  4. 6 cm on the other side

Explanation

With the lens formula 1/f = 1/v − 1/u and u = −15 cm, 1/v = 1/10 − 1/15 = 1/30, so v = +30 cm. The positive sign means a real image on the far side of the lens.

Question 24Subject-specific content knowledge

'The pen is mightier than the sword.' The figure of speech used here is:

  1. Metonymy Correct answer.
  2. Onomatopoeia
  3. Hyperbole
  4. Simile

Explanation

Metonymy substitutes a thing for a concept closely associated with it: the pen stands for writing and ideas, the sword for armed force. No explicit comparison or sound imitation is present.

Question 25Subject-specific content knowledge

The time complexity of binary search on a sorted array of n elements is:

  1. O(log n) Correct answer.
  2. O(1)
  3. O(n log n)
  4. O(n)

Explanation

Each comparison halves the interval still to be searched, so the number of steps grows with log₂n. This halving is why binary search is far faster than a sequential scan on large inputs.

Question 26Subject-specific content knowledge

The sum of the interior angles of a regular hexagon is:

  1. 900°
  2. 1080°
  3. 720° Correct answer.
  4. 540°

Explanation

For a polygon with n sides, the interior angles add up to (n − 2) × 180°. Substituting n = 6 gives 4 × 180° = 720°.

Question 27Subject-specific content knowledge

The identity of an element is determined by its atomic number, which equals the number of:

  1. Electrons in the outermost shell
  2. Protons in the nucleus Correct answer.
  3. Mass number
  4. Neutrons in the nucleus

Explanation

The atomic number (Z) is the number of protons in the nucleus and is unique to each element. In a neutral atom it also equals the total number of electrons.

Question 28Subject-specific content knowledge

The word 'lucid' is closest in meaning to:

  1. Confusing
  2. Clear Correct answer.
  3. Lengthy
  4. Dark

Explanation

'Lucid' describes something expressed clearly and easy to follow, especially speech or writing. It is used figuratively in the sense of shedding light on a subject.

Question 29Subject-specific content knowledge

In a eukaryotic cell, the organelle that is the main site of aerobic respiration and ATP production is the:

  1. Ribosome
  2. Mitochondrion Correct answer.
  3. Lysosome
  4. Golgi apparatus

Explanation

Mitochondria host the Krebs cycle and the electron transport chain, generating most of the cell's ATP. Their inner membrane is folded into cristae to increase the surface area for these reactions.

Question 30Subject-specific content knowledge

The largest province of Pakistan by area is:

  1. Khyber Pakhtunkhwa
  2. Punjab
  3. Sindh
  4. Balochistan Correct answer.

Explanation

Balochistan covers roughly 44 per cent of Pakistan's land area, making it the largest province by area. Its population, however, is the smallest among the provinces.

Question 31Subject-specific content knowledge

In computing, one kilobyte (1 KB) is equal to:

  1. 1000 bytes
  2. 1024 bits
  3. 1024 bytes Correct answer.
  4. 8 bytes

Explanation

In the binary convention used in computing, 1 KB = 2^10 bytes = 1024 bytes. Storage is organised in powers of two rather than powers of ten.

Question 32Subject-specific content knowledge

The first caliph of Islam after the Prophet Muhammad (peace be upon him) was:

  1. Umar ibn al-Khattab (RA)
  2. Uthman ibn Affan (RA)
  3. Abu Bakr Siddiq (RA) Correct answer.
  4. Ali ibn Abi Talib (RA)

Explanation

Abu Bakr Siddiq (RA) was chosen as the first caliph in 11 AH (632 CE) and led the community for about two years. The order of the rightly guided caliphs is Abu Bakr, Umar, Uthman and Ali (RA).

Question 33Subject-specific content knowledge

If x + 1/x = 3, then the value of x² + 1/x² is:

  1. 11
  2. 6
  3. 9
  4. 7 Correct answer.

Explanation

Squaring both sides gives x² + 2 + 1/x² = 9. Subtracting the middle term of 2 leaves x² + 1/x² = 7.

Question 34Subject-specific content knowledge

A body of mass 2 kg moving with a speed of 3 m/s has kinetic energy equal to:

  1. 12 J
  2. 6 J
  3. 18 J
  4. 9 J Correct answer.

Explanation

Kinetic energy is given by KE = ½mv². Substituting m = 2 kg and v = 3 m/s gives ½ × 2 × 9 = 9 J.

Question 35Subject-specific content knowledge

Which of the following substances is an ionic compound?

  1. NaCl Correct answer.
  2. CO₂
  3. CH₄
  4. H₂O

Explanation

Sodium chloride is formed by electron transfer from a metal to a non-metal, producing Na⁺ and Cl⁻ ions held by electrostatic attraction. The other three are made of non-metals only and are covalently bonded.

Question 36Subject-specific content knowledge

The number of chromosomes in a normal human somatic (body) cell is:

  1. 23
  2. 44
  3. 48
  4. 46 Correct answer.

Explanation

Human body cells are diploid, containing 23 pairs of chromosomes, which gives a total of 46. Gametes are haploid and carry only 23 chromosomes each.

Question 37Subject-specific content knowledge

Choose the correct indirect speech form of: He said, "I am busy."

  1. He said that he was busy. Correct answer.
  2. He said that he is busy.
  3. He says that he was busy.
  4. He said that I am busy.

Explanation

In reported speech the reporting verb is past, so the present tense of the original is backshifted to the past and the first-person pronoun changes to match the reporter. This yields 'He said that he was busy.'

Question 38Subject-specific content knowledge

In a relational database, a primary key is a field that:

  1. May contain duplicate values in a table
  2. Identifies every row uniquely Correct answer.
  3. Must always be a numeric value
  4. Can be left null in a row

Explanation

A primary key enforces entity integrity: each value must be unique and non-null so that every record can be identified without ambiguity. It may be numeric or textual.

Question 39Subject-specific content knowledge

The value of sin 30° + cos 60° is:

  1. √3/2
  2. 0
  3. 1/2
  4. 1 Correct answer.

Explanation

For complementary angles, sin 30° and cos 60° both equal 1/2. Their sum is therefore 1.

Question 40Subject-specific content knowledge

Three resistors, each of 3 Ω, are connected in parallel. The equivalent resistance of the combination is:

  1. 9 Ω
  2. 3 Ω
  3. 6 Ω
  4. 1 Ω Correct answer.

Explanation

For resistors in parallel, 1/R = 1/3 + 1/3 + 1/3 = 1, so R = 1 Ω. Identical resistors in parallel give a value equal to one resistance divided by the number of resistors.

Question 41Subject-specific content knowledge

The general formula of the alkane homologous series is:

  1. CₙH₂ₙ₊₂ Correct answer.
  2. CₙH₂ₙ
  3. CₙH₂ₙ₋₂
  4. CₙH₂ₙ₊₁OH

Explanation

Alkanes are saturated hydrocarbons containing only single bonds, so each molecule holds the maximum possible number of hydrogen atoms, CₙH₂ₙ₊₂. For example, ethane is C₂H₆.

Question 42Subject-specific content knowledge

In green plants, the light-dependent reactions of photosynthesis take place in the:

  1. Nucleus
  2. Ribosome
  3. Mitochondria
  4. Chloroplast Correct answer.

Explanation

Chloroplasts contain the pigment chlorophyll arranged in thylakoid membranes, where light energy is captured and converted to ATP and NADPH. The Calvin cycle then uses these products in the stroma.

Question 43Subject-specific content knowledge

Which protocol is used by a web browser to request pages from a web server?

  1. HTTP Correct answer.
  2. SMTP
  3. TCP
  4. FTP

Explanation

HTTP (HyperText Transfer Protocol) defines the request and response messages exchanged between a browser and a web server. Its secure form, HTTPS, adds encryption through TLS.

Question 44Subject-specific content knowledge

The speed of sound is greatest in which of the following media?

  1. Vacuum
  2. Water
  3. Air
  4. Steel Correct answer.

Explanation

Sound needs a material medium, and it travels fastest in solids because their tightly packed, strongly bonded particles transmit vibrations quickly. Steel is therefore the fastest of the listed media.

Question 45Subject-specific content knowledge

If matrix A has order 2 × 3 and matrix B has order 3 × 4, then the order of the product AB is:

  1. 2 × 4 Correct answer.
  2. 3 × 3
  3. 4 × 2
  4. Undefined

Explanation

Two matrices can be multiplied only when the number of columns of the first equals the number of rows of the second. Here 3 = 3, and the product takes the outer dimensions, 2 rows and 4 columns.

Question 46Subject-specific content knowledge

A particle executing simple harmonic motion has its maximum acceleration at:

  1. Every point of its path, since acceleration is constant
  2. The mean position
  3. The extreme position Correct answer.
  4. A point midway between mean and extreme position

Explanation

In simple harmonic motion the acceleration is proportional to displacement, a = −ω²x, and is directed towards the mean position. Its magnitude therefore peaks where the displacement is largest, at the extreme positions.

Question 47Subject-specific content knowledge

Among Na, Mg, Al and Si, the element with the highest first ionisation energy is:

  1. Al
  2. Mg
  3. Si Correct answer.
  4. Na

Explanation

First ionisation energy generally increases across a period as nuclear charge grows while the added electrons enter the same shell. Silicon, being furthest right of the four, has the highest value, though aluminium dips slightly below magnesium because its outer electron is in a more shielded 3p orbital.

Question 48Subject-specific content knowledge

A colour-blind man marries a woman who is homozygous normal for colour vision. Their children will be:

  1. Half of the sons will be colour blind
  2. All daughters carriers; sons normal Correct answer.
  3. All sons will be colour blind
  4. All daughters will be colour blind

Explanation

Colour blindness is X-linked recessive. The father passes his affected X chromosome to every daughter, making them carriers, and his Y chromosome to every son, so all sons receive the mother's normal X and have normal vision.

Question 49Subject-specific content knowledge

If the roots of the equation x² + bx + c = 0 are 2 and 3, then the value of b + c is:

  1. 5
  2. 1 Correct answer.
  3. −1
  4. 11

Explanation

For x² + bx + c = 0, the sum of the roots equals −b and the product equals c. Hence b = −(2 + 3) = −5 and c = 2 × 3 = 6, giving b + c = 1.

Question 50Subject-specific content knowledge

An element has the electron configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹. To which group and period of the periodic table does it belong?

  1. Group 1, Period 3
  2. Group 4, Period 1
  3. Group 2, Period 4
  4. Group 1, Period 4 Correct answer.

Explanation

The highest occupied shell is the fourth shell, indicated by the 4s¹ subshell, so the element lies in Period 4. It has one electron in its outermost shell, which places it in Group 1 of the periodic table.