IB Practice Test — 50 Questions Across All Subjects

This practice test covers 5 questions from each of 10 IB Diploma Programme subjects. The questions span both SL and HL content and reflect the analytical, evaluative style that IB exams demand. Work through the test under timed conditions before checking the answer key.

• Time limit: 60 minutes (72 seconds per question)
• Format: Multiple choice — select the best answer from options A–D
• Marking: 1 mark per question, 50 marks total
• Conditions: Attempt without notes. Record your answers on a separate sheet.
• After the test: Check the answer key at the bottom. Study the explanations for any questions you got wrong.

Which statement about enzyme competitive inhibition is correct?

Correct: B (index 1)

Competitive inhibitors compete with substrate for the active site. Increasing substrate concentration can outcompete the inhibitor, so the effect is reversible. $V_{max}$ remains unchanged — only the apparent $K_m$ increases. Non-competitive inhibitors bind to allosteric sites and reduce $V_{max}$.

medium — 1 mark

In a dihybrid cross between two heterozygous parents (AaBb × AaBb) with independent assortment, what fraction of the offspring are expected to show both dominant phenotypes?

Correct: C (index 2)

For independent assortment, the probability of both dominant phenotypes = $P(A\_) \times P(B\_) = \frac{3}{4} \times \frac{3}{4} = \frac{9}{16}$. This is the classic 9:3:3:1 ratio from Mendel’s law of independent assortment.

medium — 1 mark

Which of the following best describes primary succession?

Correct: B (index 1)

Primary succession begins on bare rock or newly exposed surfaces (e.g., after a volcanic eruption or glacial retreat) where no soil exists. Secondary succession occurs where soil remains after a disturbance. The pioneer species in primary succession are lichens and mosses that help create soil.

easy — 1 mark

The cardiac cycle includes the period of systole. During ventricular systole:

Correct: C (index 2)

During ventricular systole, the ventricles contract. The atrioventricular valves close (producing the first heart sound), and the semilunar valves open to allow blood to be ejected into the pulmonary artery and aorta.

medium — 1 mark

During translation, the ribosome moves along the mRNA in the:

Correct: B (index 1)

The ribosome reads mRNA in the 5’ to 3’ direction, synthesising the polypeptide from the N-terminus to the C-terminus. This is the same direction as mRNA synthesis (transcription), but the processes occur in different locations in eukaryotic cells.

medium — 1 mark

What is the empirical formula of a compound containing 40% carbon, 6.7% hydrogen, and 53.3% oxygen by mass?

Correct: A (index 0)

Assume 100 g: C = 40 g (3.33 mol), H = 6.7 g (6.7 mol), O = 53.3 g (3.33 mol). Divide by smallest (3.33): C = 1, H = 2, O = 1. Empirical formula = $\text{CH}_2\text{O}$.

easy — 1 mark

Which element has the highest first ionisation energy in Period 3 of the periodic table?

Correct: D (index 3)

Across a period, first ionisation energy generally increases due to increasing nuclear charge and decreasing atomic radius. Chlorine has the highest nuclear charge among the listed elements and the smallest atomic radius, so it holds its outer electrons most tightly.

medium — 1 mark

Which molecule has the largest bond angle?

Correct: D (index 3)

$\text{SF}_6$ has bond angles of 90° between adjacent bonds in its octahedral geometry. $\text{CH}_4$ has 109.5°, $\text{NH}_3$ has approximately 107°, and $\text{H}_2\text{O}$ has approximately 104.5°. However, “largest bond angle” depends on interpretation — $\text{CH}_4$ at 109.5° is the largest single angle. $\text{SF}_6$ has the most bonds arranged symmetrically at 90°.

hard — 1 mark

Hess’s law states that:

Correct: B (index 1)

Hess’s law states that the total enthalpy change for a reaction is independent of the pathway taken, because enthalpy is a state function. This allows us to calculate enthalpy changes for reactions that cannot be measured directly by constructing alternative routes using known reactions.

easy — 1 mark

Which reagent is used to distinguish between an aldehyde and a ketone?

Correct: C (index 2)

Tollens’ reagent (silver-ammonia complex) is reduced by aldehydes to produce a silver mirror. Ketones do not react with Tollens’ reagent. Bromine water can also distinguish them (aldehydes decolourise it), but Tollens’ reagent is the most specific test.

medium — 1 mark

A projectile is launched at 30 m/s at an angle of 60° to the horizontal. What is the horizontal component of the initial velocity? ($\cos 60° = 0.5$)

Correct: A (index 0)

$v_x = v \cos \theta = 30 \times \cos 60° = 30 \times 0.5 = 15 \text{ m/s}$.

easy — 1 mark

Two speakers emit sound waves of the same frequency. At a certain point, the path difference between the two waves is $1.5\lambda$. This results in:

Correct: B (index 1)

For destructive interference, the path difference must be an odd multiple of $\frac{\lambda}{2}$. Here, $1.5\lambda = 3 \times \frac{\lambda}{2}$, which is an odd multiple (3) of half-wavelengths. The waves arrive in antiphase and cancel.

medium — 1 mark

A wire of length $L$ carrying current $I$ is placed in a uniform magnetic field $B$ at right angles. What is the magnitude of the force on the wire?

Correct: A (index 0)

The force on a current-carrying conductor in a magnetic field is $F = BIL \sin \theta$. When the wire is perpendicular to the field ($\theta = 90°$), $\sin \theta = 1$, so $F = BIL$.

easy — 1 mark

According to the photoelectric effect, the maximum kinetic energy of emitted electrons depends on:

Correct: B (index 1)

Einstein’s photoelectric equation: $KE_{max} = hf - \phi$, where $hf$ is the photon energy and $\phi$ is the work function. The kinetic energy depends on the frequency (and thus energy) of individual photons, not the intensity (which affects the number of electrons emitted).

medium — 1 mark

In an adiabatic process for an ideal gas:

Correct: B (index 1)

An adiabatic process is one in which no heat is exchanged with the surroundings ($Q = 0$). This can occur either because the system is perfectly insulated or because the process happens too quickly for heat transfer. Temperature and pressure both change during an adiabatic process.

easy — 1 mark

Simplify $\frac{x^2 - 9}{x + 3}$ for $x \neq -3$.

Correct: A (index 0)

$x^2 - 9 = (x+3)(x-3)$ by difference of squares. $\frac{(x+3)(x-3)}{x+3} = x - 3$ for $x \neq -3$.

easy — 1 mark

If $f(x) = \ln(2x - 1)$, what is the domain of $f$?

Correct: B (index 1)

The argument of the natural logarithm must be positive: $2x - 1 > 0$, so $2x > 1$, giving $x > \frac{1}{2}$.

easy — 1 mark

What is the derivative of $f(x) = x^3 \sin x$?

Correct: C (index 2)

Using the product rule: $\frac{d}{dx}(uv) = u\frac{dv}{dx} + v\frac{du}{dx}$. Let $u = x^3$ and $v = \sin x$. Then $f'(x) = x^3 \cos x + 3x^2 \sin x$.

medium — 1 mark

The variance of the data set $\{2, 4, 4, 4, 5, 5, 7, 9\}$ is:

Correct: A (index 0)

Mean = $\frac{2+4+4+4+5+5+7+9}{8} = \frac{40}{8} = 5$.

Variance = $\frac{(2-5)^2 + 3(4-5)^2 + 2(5-5)^2 + (7-5)^2 + (9-5)^2}{8} = \frac{9+3+0+4+16}{8} = \frac{32}{8} = 4$.

medium — 1 mark

In a triangle, $a = 8$, $b = 6$, and $C = 60°$. What is the area of the triangle?

Correct: A (index 0)

Area = $\frac{1}{2}ab\sin C = \frac{1}{2} \times 8 \times 6 \times \sin 60° = 24 \times \frac{\sqrt{3}}{2} = 12\sqrt{3}$.

medium — 1 mark

The price elasticity of demand for a good is −0.3. This means demand is:

Correct: B (index 1)

When $|\text{PED}| < 1$, demand is price inelastic — a given percentage change in price causes a smaller percentage change in quantity demanded. This is typical for necessities and goods with few substitutes.

easy — 1 mark

A merit good is one that:

Correct: B (index 1)

Merit goods (e.g., education, healthcare) are underconsumed because individuals underestimate their private benefits. Governments intervene through subsidies, free provision, or legislation to increase consumption.

medium — 1 mark

The multiplier effect in Keynesian economics describes how:

Correct: B (index 1)

The multiplier effect occurs because one person’s spending becomes another person’s income, which is then partly spent again. The multiplier = $\frac{1}{1 - MPC}$, where $MPC$ is the marginal propensity to consume.

medium — 1 mark

A tariff on imported goods will:

Correct: C (index 2)

A tariff is a tax on imports. It raises the price of imported goods (reducing imports), increases domestic production (protecting domestic firms), reduces consumer surplus, but generates tariff revenue for the government.

medium — 1 mark

Which indicator is NOT used to measure economic development?

Correct: D (index 3)

GDP per capita, life expectancy, and literacy rate are all development indicators. A stock market index measures financial market performance, which does not directly indicate the wellbeing or development level of a population.

easy — 1 mark

Which greenhouse gas has the highest global warming potential per molecule?

Correct: C (index 2)

Nitrous oxide ($\text{N}_2\text{O}$) has a global warming potential approximately 273 times that of $\text{CO}_2$ over 100 years. Methane is about 80 times more potent than $\text{CO}_2$. However, $\text{CO}_2$ contributes most to total warming due to its much greater concentration.

medium — 1 mark

The demographic transition model describes:

Correct: B (index 1)

The demographic transition model shows how birth and death rates change as countries develop through stages: from high birth and death rates (pre-industrial), through falling death rates (transitional), to low birth and death rates (post-industrial).

easy — 1 mark

Urban sprawl refers to:

Correct: B (index 1)

Urban sprawl is the uncontrolled, low-density expansion of cities into rural land. It leads to increased car dependency, loss of agricultural land, habitat destruction, and higher infrastructure costs.

easy — 1 mark

Which of the following is a renewable resource?

Correct: C (index 2)

Solar energy is renewable — it is replenished naturally on a human timescale. Natural gas, coal, and uranium are finite resources that take millions of years to form and cannot be replaced once consumed.

easy — 1 mark

A drainage basin is defined as:

Correct: A (index 0)

A drainage basin (catchment area) is an area of land where all water drains to a common outlet, such as a river mouth or lake. It is bounded by a watershed — the high ground separating adjacent drainage basins.

easy — 1 mark

The policy of containment during the Cold War aimed to:

Correct: A (index 0)

Containment was the US strategy to prevent the spread of communism. It was articulated in the Truman Doctrine (1947) and guided US foreign policy throughout the Cold War, including the Marshall Plan, NATO, and interventions in Korea and Vietnam.

easy — 1 mark

Which of the following was a feature of Stalin’s rule in the Soviet Union?

Correct: B (index 1)

Stalin implemented a centrally planned economy where the state controlled all means of production, set production targets, and allocated resources. This replaced the mixed economy of the New Economic Policy (NEP).

easy — 1 mark

The Treaty of Versailles (1919) imposed which of the following on Germany?

Correct: C (index 2)

The Treaty of Versailles imposed the “war guilt clause” (Article 231), which held Germany responsible for WWI, and required Germany to pay reparations. It also limited German military size and ceded territory. These terms fuelled German resentment and contributed to the rise of Nazism.

easy — 1 mark

The Enlightenment was characterised by:

Correct: B (index 1)

The Enlightenment (17th–18th centuries) emphasised reason, scientific method, individual liberty, and the separation of church and state. Thinkers like Locke, Voltaire, and Rousseau challenged traditional authority and laid the intellectual foundations for democratic revolutions.

easy — 1 mark

The process of decolonisation in Africa was accelerated by:

Correct: B (index 1)

European powers were economically and militarily weakened by WWII. Combined with rising nationalist movements, Pan-Africanism, and international pressure (including from the US and USSR), this led to rapid decolonisation across Africa in the 1950s and 1960s.

medium — 1 mark

In literary analysis, what does the term “juxtaposition” refer to?

Correct: B (index 1)

Juxtaposition is the placement of two contrasting elements near each other to highlight their differences. For example, describing a wealthy neighbourhood next to a slum to emphasise inequality. It is distinct from alliteration (A), allusion (C), and imagery (D).

easy — 1 mark

Which rhetorical device involves asking a question not to receive an answer but to make a point?

Correct: B (index 1)

A rhetorical question is asked for effect, not to elicit an answer. The speaker or writer uses it to emphasise a point or prompt the audience to think. For example: “Is the sky blue?” — the answer is obvious and not expected.

easy — 1 mark

In the context of poetry, what is a “sonnet”?

Correct: B (index 1)

A sonnet is a 14-line poem written in iambic pentameter with a specific rhyme scheme. The two main forms are the Shakespearean (three quatrains + couplet, ABAB CDCD EFEF GG) and Petrarchan (octave + sestet, ABBAABBA + CDECDE or similar).

easy — 1 mark

In a persuasive text, what is the purpose of using statistics and data?

Correct: C (index 2)

Statistics and data appeal to logos — the logical aspect of persuasion. They provide concrete evidence to support claims. Establishing credibility is ethos (D); emotional weight is pathos (B).

medium — 1 mark

The concept of “register” in language refers to:

Correct: B (index 1)

Register describes the level of formality in language use. For example, legal writing uses a formal register, while texting friends uses an informal register. Choosing the appropriate register is essential for effective communication.

easy — 1 mark

What is the time complexity of binary search on a sorted array of $n$ elements?

Correct: C (index 2)

Binary search repeatedly divides the search space in half. With each comparison, the remaining search area is halved, so the number of comparisons is $\log_2 n$. This is significantly faster than linear search ($O(n)$) for large arrays.

medium — 1 mark

How many bits are needed to represent the decimal number 255 in binary?

Correct: B (index 1)

$2^8 = 256$, so 8 bits can represent values from 0 to 255. The binary representation of 255 is 11111111 (eight 1s).

easy — 1 mark

What is the output of the Boolean expression: NOT (TRUE AND FALSE)?

Correct: A (index 0)

TRUE AND FALSE evaluates to FALSE. NOT FALSE evaluates to TRUE.

easy — 1 mark

In object-oriented programming, what is “polymorphism”?

Correct: B (index 1)

Polymorphism allows objects of different types to be accessed through a common interface. For example, a Shape superclass with a draw() method, where Circle and Rectangle subclasses each implement draw() differently.

medium — 1 mark

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

Correct: C (index 2)

HTTP (Hypertext Transfer Protocol) and its secure version HTTPS are used to transfer web pages and related content between servers and browsers. FTP transfers files; SMTP sends email; SSH provides secure remote access.

easy — 1 mark

Which neurotransmitter is primarily associated with mood regulation and is targeted by SSRIs?

Correct: C (index 2)

Serotonin is a neurotransmitter involved in mood, sleep, and appetite. SSRIs (Selective Serotonin Reuptake Inhibitors) block the reabsorption of serotonin, increasing its availability in the synapse. They are commonly prescribed for depression and anxiety.

easy — 1 mark

According to Baddeley’s working memory model, which component processes verbal and acoustic information?

Correct: C (index 2)

The phonological loop processes verbal and acoustic information through two sub-components: the phonological store (inner ear) and the articulatory control process (inner voice). It is responsible for the serial position effect in free recall.

medium — 1 mark

Piaget’s stage of formal operational thinking is characterised by:

Correct: B (index 1)

The formal operational stage (approximately 11+ years) is characterised by the ability to think abstractly, reason hypothetically, and use deductive logic. Object permanence (A) develops in the sensorimotor stage; conservation (C) in concrete operational; egocentrism (D) diminishes in concrete operational.

medium — 1 mark

Asch’s conformity experiments demonstrated that:

Correct: B (index 1)

Asch (1951) found that participants would give clearly incorrect answers (matching the confederate majority) about 37% of the time. This demonstrated that social pressure from a group can lead individuals to conform even when the correct answer is obvious.

medium — 1 mark

The “diathesis-stress model” of psychological disorders suggests that:

Correct: B (index 1)

The diathesis-stress model proposes that psychological disorders arise from an interaction between a pre-existing vulnerability (diathesis) — which may be genetic, biological, or psychological — and environmental stressors. Neither factor alone is sufficient; both are necessary.

medium — 1 mark

• Biology — Cell biology, molecular biology, genetics, ecology, and human physiology
• Chemistry — Stoichiometry, atomic structure, bonding, energetics, and organic chemistry
• Physics — Mechanics, waves, electricity, quantum physics, and thermal physics
• Mathematics — Number and algebra, functions, calculus, statistics, and geometry
• Economics — Microeconomics, macroeconomics, international economics, and development
• Geography — Climate change, population, urbanisation, and resources
• History — Cold War, authoritarian states, and decolonisation
• English — Literary analysis, rhetoric, and poetry
• Computer Science — Algorithms, data representation, networks, and OOP
• Psychology — Biological, cognitive, developmental, social, and abnormal psychology

1. Time yourself. 60 minutes for 50 questions mirrors the pace of IB Paper 1 exams.
2. Apply IB command terms. IB questions test whether you can analyse, evaluate, and discuss — not just recall facts.
3. Study explanations for wrong answers. The explanations are designed to address common IB misconceptions.
4. Use this alongside topic notes. If you get several questions wrong in one subject, revisit the topic notes for that area.
5. Retake after one week. Spaced repetition is the most effective way to retain information.

Last updated: 24 July 2026

Written by Wyatt. For questions or feedback, visit wyattau.com.