IB Practice Questions v12-beta

v12-beta · 120 道题·每Q加topic-code与锚点 · 与Syllabus v3双向对齐

v10: 点击选项答题,自动记录到错题本(localStorage)。

v12新增:考纲Topic ↔ Q编号双向锚点直达(锚点#q-N跳题;topic-code反向查考纲)

Sample Questions

Mathematics (19 questions)

【G5-MAA-54】 Q1 · IB Math AA HL · Calculus · Medium

Find the maximum value of f(x) = x³ - 6x² + 9x + 2 on the interval [0, 4].

Answer: A) 6. f'(x) = 3x² - 12x + 9 = 0 → x=1 or x=3. f(1)=6, f(3)=2, f(0)=2, f(4)=6. Maximum is 6 at x=1.
【G5-MAA-51】 Q4 · IB Math AA HL · Algebra · Medium

Given log₂(x) + log₂(x-2) = 3, find x.

Answer: A) 4. log₂(x(x-2))=3, x(x-2)=8, x²-2x-8=0, (x-4)(x+2)=0, x=4 (x=-2 rejected since log of negative is undefined).
【G5-MAA-52】 Q5 · IB Math AA HL · Functions · Hard

If f(x) = 2x + 1 and g(x) = x² - 3, find g(f(2)).

Answer: A) 22. f(2)=2(2)+1=5, g(5)=5²-3=22.
【G5-MAA-51】 Q11 · IB Math AA HL · Algebra · Easy

Solve: 2^x = 32.

Answer: C) 5. 2^5 = 32.
【G5-MAA-54】 Q12 · IB Math AA HL · Calculus · Medium

Find dy/dx if y = 3x⁴ - 2x² + 5.

Answer: A) 12x³ - 4x. Power rule: 4·3x³ - 2·2x = 12x³ - 4x.
【G5-MAA-55】 Q13 · IB Math AA HL · Statistics · Medium

In a normal distribution with mean 50 and SD 10, what percentage of data lies between 40 and 60?

Answer: A) 68%. 40 and 60 are ±1 SD from mean, covering ~68% of data.
【G5-MAA-53】 Q14 · IB Math AA HL · Vectors · Hard

Given u = (3, 4), find |u|.

Answer: C) 5. |u| = √(9+16) = √25 = 5.
【G5-MAA-51】 Q21 · IB Math AA HL · Sequences · Easy

Find the 10th term of the arithmetic sequence 3, 7, 11, 15, ...

Answer: A) 39. a_n = a_1 + (n-1)d = 3 + 9×4 = 39.
【G5-MAA-51】 Q22 · IB Math AA HL · Binomial Theorem · Medium

Find the coefficient of x³ in the expansion of (1 + 2x)⁵.

Answer: C) 80. C(5,3)·(2x)³ = 10·8x³ = 80x³, so the coefficient is 80.
【G5-MAA-51】 Q23 · IB Math AA HL · Complex Numbers · Medium

Find the modulus of the complex number z = 3 + 4i.

Answer: B) 5. |z| = √(3² + 4²) = √25 = 5.
【G5-MAA-54】 Q24 · IB Math AA HL · Integration · Hard

Evaluate ∫ x·e^x dx.

Answer: B) e^x(x - 1) + C. Using parts with u=x, dv=e^x dx: ∫x·e^x dx = x·e^x - ∫e^x dx = x·e^x - e^x = e^x(x-1) + C.
【G5-MAI-510】 Q25 · IB Math AI HL · Probability Distributions · Medium

A fair coin is tossed 5 times. What is the probability of getting exactly 3 heads?

Answer: B) 10/32. P(X=3) = C(5,3)·(1/2)⁵ = 10/32 = 5/16.
【G5-MAA-51】 Q26 · IB Math AA HL · Matrices · Hard

Given matrix A = [[2, 1], [1, 3]], find A² (the matrix product A·A).

Answer: A) [[5, 5], [5, 10]]. Row-by-column: row 1 = [2·2+1·1, 2·1+1·3] = [5, 5]; row 2 = [1·2+3·1, 1·1+3·3] = [5, 10].
【G5-MAA-54】 Q27 · IB Math AA HL · Limits · Medium

Evaluate lim(x→2) (x² - 4)/(x - 2).

Answer: B) 4. Factor: (x-2)(x+2)/(x-2) = x+2 → 4 as x→2.
【G5-MAA-53】 Q28 · IB Math AA HL · Trigonometric Identities · Hard

Simplify: sin²θ + cos²θ + tan²θ.

Answer: B) sec²θ. Using sin²θ + cos²θ = 1, the expression becomes 1 + tan²θ = sec²θ.
【G5-MAA-51】 Q29 · IB Math AA HL · Logarithms · Medium

Solve: log(x) + log(x+3) = 1 (base 10).

Answer: A) 2. log(x(x+3))=1, x(x+3)=10, x²+3x-10=0, (x-2)(x+5)=0, x=2 (x=-5 rejected since log of negative is undefined).
【G5-MAA-54】 Q30 · IB Math AA HL · Optimization · Hard

A rectangle has perimeter 20 m. What is the maximum possible area?

Answer: A) 25 m². If length = x, width = 10-x, area = x(10-x) = 10x - x². Maximum at x = 5: area = 25 m² (square is optimal).
【G5-MAA-54】 Q31 · IB Math AA HL · Differential Equations · Hard

Solve dy/dx = 2x, given y(0) = 3.

Answer: A) y = x² + 3. Integrate: y = x² + C. Use y(0)=3: C = 3. So y = x² + 3.
【G5-MAA-53】 Q32 · IB Math AA HL · Vector Geometry · Medium

Find the dot product of vectors a = (2, -1, 3) and b = (4, 2, -1).

Answer: A) 3. a·b = (2)(4) + (-1)(2) + (3)(-1) = 8 - 2 - 3 = 3.

Physics (16 questions)

【G4-Phy-42】 Q2 · IB Physics HL · Mechanics · Easy

A ball is thrown vertically upward at 20 m/s. What is the maximum height reached? (g = 10 m/s²)

Answer: B) 20 m. v² = u² - 2gh, 0 = 400 - 20h, h = 20 m.
【G4-Phy-44】 Q6 · IB Physics HL · Waves · Medium

A wave has frequency 500 Hz and speed 340 m/s. What is its wavelength?

Answer: B) 0.68 m. λ = v/f = 340/500 = 0.68 m.
【G4-Phy-43】 Q7 · IB Physics HL · Thermodynamics · Hard

An ideal gas at 300 K has its temperature doubled to 600 K at constant volume. If the initial pressure was 100 kPa, what is the new pressure?

Answer: C) 200 kPa. At constant volume, P/T = constant. P₂ = P₁ × T₂/T₁ = 100 × 600/300 = 200 kPa.
【G4-Phy-42】 Q15 · IB Physics HL · Mechanics · Easy

A car decelerates from 30 m/s to 0 in 6 seconds. What is the deceleration?

Answer: B) -5 m/s². a = Δv/Δt = (0-30)/6 = -5 m/s².
【G4-Phy-45】 Q16 · IB Physics HL · Electricity · Medium

A 12V battery drives 3A through a circuit. What is the resistance?

Answer: B) 4Ω. R = V/I = 12/3 = 4Ω.
【G4-Phy-47】 Q17 · IB Physics HL · Modern Physics · Hard

What is the energy of a photon with frequency 5×10¹⁴ Hz? (h = 6.6×10⁻³⁴ J·s)

Answer: A) 3.3×10⁻¹⁹ J. E = hf = 6.6×10⁻³⁴ × 5×10¹⁴ = 3.3×10⁻¹⁹ J.
【G4-Phy-46】 Q33 · IB Physics HL · Circular Motion · Easy

A car goes around a circular track of radius 50 m at constant speed 10 m/s. What is its centripetal acceleration?

Answer: B) 2 m/s². a_c = v²/r = 100/50 = 2 m/s².
【G4-Phy-44】 Q34 · IB Physics HL · SHM · Medium

A mass on a spring has period 2π s. If the spring constant k = 10 N/m, what is the mass? (Take π² ≈ 10)

Answer: C) 10 kg. T = 2π√(m/k). With T = 2π: √(m/k) = 1, so m = k = 10 kg.
【G4-Phy-45】 Q35 · IB Physics HL · Electromagnetic Induction · Medium

A magnetic flux through a coil changes from 0.05 Wb to 0.15 Wb in 0.2 s. The coil has 50 turns. What is the magnitude of the induced EMF?

Answer: B) 25 V. EMF = N·|ΔΦ|/Δt = 50 × (0.10)/0.2 = 25 V.
【G4-Phy-47】 Q36 · IB Physics HL · Nuclear Physics · Hard

A radioactive isotope has a half-life of 6 hours. If you start with 80 g, how much remains after 18 hours?

Answer: A) 10 g. 18 hours = 3 half-lives. 80 → 40 → 20 → 10 g.
【G4-Phy-44】 Q37 · IB Physics HL · Optics · Medium

A converging lens has focal length 20 cm. An object is placed 60 cm from the lens. At what distance from the lens is the image formed?

Answer: B) 30 cm. 1/v = 1/f - 1/u = 1/20 - 1/60 = 2/60 = 1/30, so v = 30 cm.
【G4-Phy-45】 Q38 · IB Physics HL · Capacitors · Medium

A 10 μF capacitor is charged by a 12 V battery. What charge is stored?

Answer: A) 120 μC. Q = CV = 10 × 12 = 120 μC.
【G4-Phy-45】 Q39 · IB Physics HL · Magnetism · Hard

A wire of length 0.5 m carries current 4 A perpendicular to a magnetic field of 0.2 T. What is the force on the wire?

Answer: A) 0.4 N. F = BIL = 0.2 × 4 × 0.5 = 0.4 N.
【G4-Phy-47】 Q40 · IB Physics HL · Quantum · Medium

In the photoelectric effect, if light of frequency below the threshold frequency is shone on a metal, what happens?

Answer: B) No electrons are emitted. Below the threshold frequency, no electrons are emitted regardless of intensity.
【G4-Phy-43】 Q41 · IB Physics HL · Thermodynamics · Easy

How much heat is needed to raise the temperature of 2 kg of water by 5°C? (Specific heat capacity of water = 4200 J/kg·°C)

Answer: A) 42000 J. Q = mcΔT = 2 × 4200 × 5 = 42000 J.
【G4-Phy-49】 Q42 · IB Physics HL · Fluids · Medium

What is the pressure at a depth of 10 m in water? (Density of water = 1000 kg/m³, g = 10 m/s²)

Answer: B) 100000 Pa. P = ρgh = 1000 × 10 × 10 = 100000 Pa = 100 kPa.

Economics, Business & Chemistry (15 questions)

【G3-Econ-31】 Q3 · IB Economics HL · Microeconomics · Easy

Which of the following will cause a shift of the demand curve to the right?

Answer: B). Income increase shifts demand right for normal goods. A is movement along curve, C shifts left, D shifts supply.
【G3-Econ-32】 Q8 · IB Economics HL · Macroeconomics · Medium

Which of the following is an example of expansionary fiscal policy?

Answer: B). Expansionary fiscal policy involves increasing government spending or decreasing taxes to stimulate aggregate demand.
【G4-Chem-415】 Q9 · IB Chemistry HL · Equilibrium · Hard

For the reaction N₂ + 3H₂ ⇌ 2NH₃, what happens to the equilibrium when pressure is increased?

Answer: B) Shifts right. Increasing pressure shifts equilibrium toward the side with fewer moles of gas. Products have 2 moles vs 4 moles of reactants.
【G3-BM-38】 Q10 · IB Business Management HL · Marketing · Easy

Which of the following is NOT one of the 4 Ps of the marketing mix?

Answer: C) Position. The 4 Ps are Product, Price, Place, Promotion.
【G3-Econ-31】 Q18 · IB Economics HL · Microeconomics · Easy

If the price of coffee rises, what happens to demand for tea (a substitute)?

Answer: B) Increases. Substitutes: when coffee price rises, consumers switch to tea.
【G3-Econ-32】 Q19 · IB Economics HL · Macroeconomics · Medium

What is the primary tool used by central banks to control inflation?

Answer: C) Interest rates. Central banks adjust interest rates to control money supply and inflation.
【G3-BM-39】 Q20 · IB Business Management HL · Finance · Medium

A company's revenue is $500,000 and costs are $350,000. What is the profit margin?

Answer: B) 30%. Profit = $150,000. Margin = 150,000/500,000 = 30%.
【G3-Econ-31】 Q43 · IB Economics HL · Market Failure · Medium

Which of the following is an example of a negative externality?

Answer: B). Negative externalities impose costs on third parties. Pollution is a classic example. The other options are positive externalities or public goods.
【G3-Econ-32】 Q44 · IB Economics HL · Monetary Policy · Easy

To combat inflation, a central bank should:

Answer: B) Increase interest rates. Contractionary monetary policy raises rates to reduce money supply and aggregate demand.
【G3-Econ-33】 Q45 · IB Economics HL · Exchange Rates · Medium

If the US dollar appreciates against the Japanese yen, what happens to US exports to Japan?

Answer: B) They become more expensive for Japanese buyers. A stronger USD means Japanese buyers need more yen to purchase the same US goods.
【G3-BM-39】 Q46 · IB Business Management HL · Accounting · Medium

A company has current assets of $200,000 and current liabilities of $100,000. What is the current ratio?

Answer: B) 2. Current ratio = Current assets / Current liabilities = 200,000 / 100,000 = 2.
【G3-BM-37】 Q47 · IB Business Management HL · HRM · Easy

According to Maslow's hierarchy of needs, which need is at the highest level?

Answer: C) Self-actualization. Maslow's hierarchy from lowest to highest: physiological, safety, love/belonging, esteem, self-actualization.
【G4-Chem-414】 Q48 · IB Chemistry HL · Kinetics · Medium

Which factor does NOT increase the rate of a chemical reaction?

Answer: D) Decreasing surface area. Decreasing surface area reduces the rate of reaction by lowering collision frequency.
【G4-Chem-415】 Q49 · IB Chemistry HL · Equilibrium · Hard

For the exothermic reaction N₂ + 3H₂ ⇌ 2NH₃, what happens to the equilibrium when temperature is increased?

Answer: B) Equilibrium shifts left. For an exothermic reaction, increasing temperature shifts equilibrium toward the reactants (the endothermic direction).
【G4-Chem-416】 Q50 · IB Chemistry HL · Acids & Bases · Medium

What is the pH of a solution with [H⁺] = 1×10⁻⁴ M?

Answer: A) 4. pH = -log[H⁺] = -log(10⁻⁴) = 4.

Biology (10 questions)

【G4-Bio-421】 Q51 · IB Biology HL · Cell Biology · Easy

Which organelle is primarily responsible for ATP production in eukaryotic cells?

Answer: C) Mitochondrion. Mitochondria carry out aerobic cellular respiration, producing ATP via oxidative phosphorylation.
【G4-Bio-421】 Q52 · IB Biology HL · Molecular Biology · Easy

In DNA replication, which enzyme synthesizes the new complementary DNA strand?

Answer: B) DNA polymerase. DNA polymerase adds nucleotides in the 5'→3' direction using the template strand. Helicase unwinds; ligase joins Okazaki fragments.
【G4-Bio-423】 Q53 · IB Biology HL · Genetics · Medium

A heterozygous tall plant (Tt) is crossed with a homozygous short plant (tt). What is the expected ratio of tall to short offspring?

Answer: B) 1 : 1. Punnett square: Tt × tt yields 50% Tt (tall) and 50% tt (short).
【G4-Bio-424】 Q54 · IB Biology HL · Human Physiology · Medium

Which hormone is secreted by the pancreas in response to high blood glucose levels?

Answer: B) Insulin. Insulin lowers blood glucose by promoting uptake into cells and storage as glycogen. Glucagon raises blood glucose.
【G4-Bio-423】 Q55 · IB Biology HL · Ecology · Easy

Which of the following best describes a group of individuals of the same species living in the same area?

Answer: C) Population. A population is a group of conspecific individuals; a community includes multiple species; an ecosystem includes biotic + abiotic.
【G4-Bio-425】 Q56 · IB Biology HL · Evolution · Medium

The forelimbs of humans, bats, and whales have similar bone structures despite different functions. This is an example of:

Answer: B) Homologous structures. Homology indicates shared ancestry. Analogous structures result from convergent evolution (similar function, different origin).
【G4-Bio-422】 Q57 · IB Biology HL · Cell Biology · Hard

During which stage of meiosis does crossing over (recombination) between homologous chromosomes occur?

Answer: A) Prophase I. Synapsis and crossing over occur in prophase I of meiosis, producing recombinant chromatids and increasing genetic variation.
【G4-Bio-422】 Q58 · IB Biology HL · Molecular Biology · Hard

Which process converts the genetic information in mRNA into a sequence of amino acids?

Answer: C) Translation. Translation at the ribosome uses tRNA and codon-anticodon pairing to synthesize the polypeptide. Transcription makes mRNA from DNA.
【G4-Bio-423】 Q59 · IB Biology HL · Genetics · Medium

In humans, color blindness is an X-linked recessive trait. A carrier mother and unaffected father have a son. What is the probability he is colorblind?

Answer: C) 50%. Mother (XᴮXᵇ) × Father (XᴮY): sons inherit Y from father and either Xᴮ or Xᵇ from mother → 50% chance of XᵇY (colorblind).
【G4-Bio-425】 Q60 · IB Biology HL · Human Physiology · Hard

In the nephron, most reabsorption of glucose, amino acids, and water occurs in which structure?

Answer: B) Proximal convoluted tubule. The PCT reabsorbs ~70–80% of filtrate including all glucose (via cotransport), amino acids, salts, and water.

Mathematics Additional (14 questions)

【G5-MAA-54】 Q61 · IB Math AA HL · Calculus · Easy

Find the derivative of f(x) = sin(x) + cos(x).

Answer: A) cos(x) − sin(x). d/dx sin(x) = cos(x); d/dx cos(x) = −sin(x); sum gives cos(x) − sin(x).
【G5-MAA-54】 Q62 · IB Math AA HL · Calculus · Hard

Evaluate ∫₀¹ (2x + 3) dx.

Answer: B) 4. Antiderivative: x² + 3x. At x=1: 1 + 3 = 4; at x=0: 0. Definite integral = 4 − 0 = 4.
【G5-MAA-53】 Q63 · IB Math AA HL · Vectors · Medium

Vectors a = (1, 2) and b = (3, k) are perpendicular. Find k.

Answer: A) −3/2. Perpendicular ⇒ dot product = 0: 1·3 + 2·k = 0 → 3 + 2k = 0 → k = −3/2.
【G5-MAI-510】 Q64 · IB Math AI HL · Probability · Easy

A fair six-sided die is rolled once. What is the probability of rolling a number greater than 4?

Answer: A) 1/3. Numbers > 4 on a die are {5, 6}: 2 favorable outcomes out of 6, so P = 2/6 = 1/3.
【G5-MAI-510】 Q65 · IB Math AI HL · Probability · Hard

Events A and B are independent. P(A) = 0.4, P(B) = 0.5. What is P(A ∪ B)?

Answer: B) 0.7. Independent ⇒ P(A∩B) = 0.4×0.5 = 0.2. P(A∪B) = P(A)+P(B)−P(A∩B) = 0.4+0.5−0.2 = 0.7.
【G5-MAI-510】 Q66 · IB Math AI HL · Statistics · Medium

The data set {2, 4, 6, 8, 10} has mean 6. What is the standard deviation (population, ungrouped)?

Answer: B) √8. Squared deviations: (−4)², (−2)², 0², 2², 4² = 16, 4, 0, 4, 16. Variance = (40)/5 = 8. σ = √8.
【G5-MAA-51】 Q67 · IB Math AA HL · Complex Numbers · Easy

Simplify: i² + i⁴, where i = √−1.

Answer: A) 0. i² = −1, i⁴ = (i²)² = (−1)² = 1. Sum: −1 + 1 = 0.
【G5-MAA-51】 Q68 · IB Math AA HL · Complex Numbers · Medium

Write z = 1 + i in polar form (modulus–argument form).

Answer: A) √2 (cos π/4 + i sin π/4). |z| = √(1+1) = √2; arg(z) = arctan(1/1) = π/4.
【G5-MAA-51】 Q69 · IB Math AA HL · Matrices · Easy

Given A = [[1, 2], [3, 4]], find the determinant det(A).

Answer: A) −2. For 2×2 [[a,b],[c,d]], det = ad − bc = (1)(4) − (2)(3) = 4 − 6 = −2.
【G5-MAA-51】 Q70 · IB Math AA HL · Matrices · Hard

Which condition must hold for a square matrix A to have an inverse A⁻¹?

Answer: B) det(A) ≠ 0. A square matrix is invertible (non-singular) iff its determinant is nonzero. Singular matrices have det = 0.
【G5-MAA-54】 Q71 · IB Math AA HL · Calculus · Medium

Find the slope of the tangent to y = x³ at x = 2.

Answer: C) 12. dy/dx = 3x². At x = 2: 3(4) = 12. So the tangent slope is 12.
【G5-MAI-510】 Q72 · IB Math AI HL · Probability · Medium

In a normal distribution with μ = 100 and σ = 15, what z-score corresponds to x = 115?

Answer: B) 1. z = (x − μ)/σ = (115 − 100)/15 = 15/15 = 1.
【G5-MAA-53】 Q73 · IB Math AA HL · Vectors · Hard

Find the cross product a × b where a = (1, 0, 0) and b = (0, 1, 0).

Answer: A) (0, 0, 1). Standard basis cross product: î × ĵ = k̂ = (0, 0, 1), perpendicular to both with |a||b| sin 90° = 1.
【G5-MAI-510】 Q74 · IB Math AI HL · Statistics · Easy

Find the median of: 3, 7, 2, 9, 5.

Answer: A) 5. Ordered: 2, 3, 5, 7, 9. With n = 5 (odd), median is the (n+1)/2 = 3rd value = 5.

Physics Additional (12 questions)

【G4-Phy-42】 Q75 · IB Physics HL · Mechanics · Medium

A 2 kg object experiences a net force of 10 N. What is its acceleration?

Answer: B) 5 m/s². Newton's second law: F = ma ⇒ a = F/m = 10 / 2 = 5 m/s².
【G4-Phy-42】 Q76 · IB Physics HL · Mechanics · Hard

A block of mass 5 kg slides down a frictionless incline of angle 30°. What is its acceleration down the slope? (g = 10 m/s²)

Answer: B) 5 m/s². Parallel component: a = g sin θ = 10 · sin 30° = 10 × 0.5 = 5 m/s² (mass cancels on frictionless incline).
【G4-Phy-45】 Q77 · IB Physics HL · Electricity · Easy

Two resistors, 3 Ω and 6 Ω, are in parallel. What is the equivalent resistance?

Answer: B) 2 Ω. 1/Rₚ = 1/3 + 1/6 = 1/2 ⇒ Rₚ = 2 Ω (parallel: equivalent resistance is less than the smallest resistor).
【G4-Phy-45】 Q78 · IB Physics HL · Electricity · Hard

A 12 V battery with internal resistance 1 Ω is connected to a 3 Ω load. What is the terminal voltage across the load?

Answer: A) 9 V. Total R = 1 + 3 = 4 Ω ⇒ I = 12/4 = 3 A. Terminal V = I × R_load = 3 × 3 = 9 V (or 12 − I×1 = 9 V).
【G4-Phy-45】 Q79 · IB Physics HL · Magnetism · Easy

Which of the following materials is NOT ferromagnetic?

Answer: C) Copper. Fe, Ni, Co are classic ferromagnetic materials. Cu is weakly diamagnetic and not strongly attracted to magnets.
【G4-Phy-45】 Q80 · IB Physics HL · Magnetism · Medium

A charged particle moves parallel to a uniform magnetic field B. The magnetic force on the particle is:

Answer: B) Zero. Lorentz force F = qv × B, magnitude qvB sin θ. When v ∥ B, θ = 0° and sin 0° = 0 ⇒ F = 0.
【G4-Phy-44】 Q81 · IB Physics HL · Waves · Easy

Two waves of equal amplitude and frequency arrive perfectly out of phase at a point. What occurs?

Answer: B) Destructive interference. Out of phase by 180° gives A + (−A) = 0 total amplitude → destructive (node).
【G4-Phy-44】 Q82 · IB Physics HL · Waves · Hard

A string of length L fixed at both ends vibrates in its first harmonic (fundamental mode). What is the wavelength?

Answer: C) 2L. Fixed at both ends ⇒ nodes at each end. Fundamental = one loop: half a wavelength fits, so λ/2 = L ⇒ λ = 2L.
【G4-Phy-43】 Q83 · IB Physics HL · Thermodynamics · Medium

The first law of thermodynamics is a restatement of which principle?

Answer: B) Conservation of energy. ΔU = Q − W (or Q = ΔU + W) formalizes energy conservation for thermal systems.
【G4-Phy-43】 Q84 · IB Physics HL · Thermodynamics · Easy

What is absolute zero on the Celsius scale?

Answer: C) −273°C. Absolute zero = 0 K = −273.15°C, the theoretical minimum temperature where molecular motion is at minimum.
【G4-Phy-47】 Q85 · IB Physics HL · Quantum · Medium

Which phenomenon demonstrates the particle nature of light?

Answer: B) Photoelectric effect. Einstein explained the PE effect by quantized light (photons) delivering energy E = hf to eject electrons, showing particle behavior.
【G4-Phy-47】 Q86 · IB Physics HL · Quantum · Hard

Which principle states that the position and momentum of a particle cannot both be known precisely at the same time?

Answer: B) Heisenberg uncertainty principle. Δx · Δp ≥ ℏ/2, a fundamental limit of quantum mechanics. Pauli: no two fermions share identical quantum numbers.

Chemistry Additional (12 questions)

【G4-Chem-412】 Q87 · IB Chemistry HL · Bonding · Easy

Which type of bond is formed between two atoms with a large difference in electronegativity?

Answer: C) Ionic. Large ΔEN (typically > 1.7) leads to electron transfer and formation of ions (e.g., Na⁺Cl⁻).
【G4-Chem-412】 Q88 · IB Chemistry HL · Bonding · Medium

Using VSEPR theory, what is the electron domain geometry and molecular shape of NH₃?

Answer: A) Tetrahedral; trigonal pyramidal. 4 electron domains (3 bonds + 1 lone pair) ⇒ electron geometry tetrahedral; lone pair repels more ⇒ molecular shape trigonal pyramidal.
【G4-Chem-413】 Q89 · IB Chemistry HL · Energetics · Medium

A reaction has ΔH = −85 kJ mol⁻¹. This reaction is:

Answer: B) Exothermic, releasing heat. Negative ΔH means enthalpy of products < reactants; heat is released to the surroundings.
【G4-Chem-413】 Q90 · IB Chemistry HL · Energetics · Hard

Which combination of ΔH and ΔS guarantees a reaction is spontaneous at all temperatures?

Answer: C) ΔH < 0, ΔS > 0. Gibbs: ΔG = ΔH − TΔS. For ΔH negative and ΔS positive, ΔG is always negative at any T → always spontaneous.
【G4-Chem-415】 Q91 · IB Chemistry HL · Redox · Easy

In the reaction Zn + Cu²⁺ → Zn²⁺ + Cu, which species is reduced?

Answer: B) Cu²⁺. Reduction = gain of electrons (oxidation state decreases): Cu²⁺ + 2e⁻ → Cu. Zn is oxidized (loses electrons).
【G4-Chem-415】 Q92 · IB Chemistry HL · Redox · Hard

What is the oxidation number of Cl in KClO₃?

Answer: C) +5. K = +1, each O = −2. Let Cl = x: +1 + x + 3(−2) = 0 ⇒ x = +5.
【G4-Chem-416】 Q93 · IB Chemistry HL · Acids & Bases · Easy

According to the Brønsted–Lowry definition, a base is:

Answer: B) A proton acceptor. Brønsted–Lowry: acid = H⁺ donor, base = H⁺ acceptor. (Lewis: acid = e⁻ pair acceptor; base = e⁻ pair donor.)
【G4-Chem-416】 Q94 · IB Chemistry HL · Acids & Bases · Hard

What is the pH of a 0.001 M NaOH solution (assume full dissociation)?

Answer: B) 11. [OH⁻] = 0.001 M ⇒ pOH = 3. At 25°C: pH + pOH = 14 ⇒ pH = 11.
【G4-Chem-418】 Q95 · IB Chemistry HL · Organic Chemistry · Easy

Which of the following is an alkane?

Answer: B) C₂H₆. Alkanes have general formula CₙH₂ₙ₊₂ (single bonds only). C₂H₄ = alkene; C₂H₂ = alkyne; C₆H₆ = benzene (aromatic).
【G4-Chem-418】 Q96 · IB Chemistry HL · Organic Chemistry · Medium

What type of isomerism is shown by CH₃CH₂OH (ethanol) and CH₃OCH₃ (methoxymethane)?

Answer: C) Functional group. Both have molecular formula C₂H₆O but different functional groups (alcohol vs ether) → functional group isomerism (class of structural isomerism).
【G4-Chem-418】 Q97 · IB Chemistry HL · Organic Chemistry · Hard

Which reaction type converts ethene (C₂H₄) into ethanol (C₂H₅OH) by adding water across the double bond?

Answer: C) Hydration (addition). Addition of H₂O across C=C (acid-catalyzed hydration): the double bond breaks; −H and −OH add to each carbon → ethanol.
【G4-Chem-414】 Q98 · IB Chemistry HL · Kinetics · Hard

A catalyst increases the rate of a chemical reaction primarily by:

Answer: C) Providing an alternative reaction pathway with lower Eₐ. Lower Eₐ means more particles have sufficient energy to react; catalysts do not affect ΔH or equilibrium position.

Economics Additional (8 questions)

【G3-Econ-31】 Q99 · IB Economics HL · Microeconomics · Medium

If a 10% increase in price causes a 5% decrease in quantity demanded, the price elasticity of demand (PED) is:

Answer: A) −0.5 (demand is inelastic). PED = %ΔQd / %ΔP = −5%/10% = −0.5. Since |PED| < 1, demand is inelastic.
【G3-Econ-31】 Q100 · IB Economics HL · Microeconomics · Hard

Which market structure is characterized by many firms, differentiated products, and relatively easy entry/exit?

Answer: C) Monopolistic competition. Key: many firms + product differentiation (unlike perfect competition's homogeneous goods) and free entry/exit (unlike oligopoly/monopoly).
【G3-Econ-31】 Q101 · IB Economics HL · Externalities · Medium

A government imposes a per-unit Pigouvian tax on a good with negative production externalities. The intended outcome is:

Answer: B) Shift supply left, lower output toward social optimum. The tax raises producers' MPC closer to MSC, reducing overproduction and moving equilibrium closer to the socially efficient quantity.
【G3-Econ-32】 Q102 · IB Economics HL · Macroeconomics · Easy

Which of the following is included in the expenditure approach to calculating GDP?

Answer: C) Investment spending (I). Expenditure GDP = C + I + G + (X − M). Intermediate goods, transfers, and used-goods sales are excluded.
【G3-Econ-32】 Q103 · IB Economics HL · Macroeconomics · Medium

Which type of unemployment arises from a mismatch between workers' skills and available jobs?

Answer: B) Structural unemployment. Structural = skills/location mismatch (e.g., declining industry). Frictional = between jobs; cyclical = recession-related.
【G3-Econ-32】 Q104 · IB Economics HL · Fiscal Policy · Medium

In a recession, an appropriate discretionary fiscal policy response would be to:

Answer: C) Expansionary fiscal policy: higher G and/or lower T increases AD to close a recessionary gap. B and D are monetary policy tools (central bank), not fiscal.
【G3-Econ-33】 Q105 · IB Economics HL · International Trade · Easy

A country has a comparative advantage in producing a good when it can do so:

Answer: B) At a lower opportunity cost. Comparative advantage is based on opportunity cost, not absolute productivity. Gains from trade arise from specializing per CA.
【G3-Econ-33】 Q106 · IB Economics HL · Exchange Rates · Hard

In a floating exchange-rate system, an increase in demand by foreigners for a country's exports will tend to cause the country's currency to:

Answer: A) Appreciate. Foreign buyers need the domestic currency to pay for exports ⇒ demand for domestic currency rises ⇒ the currency appreciates (higher exchange value).

Business Management Additional (8 questions)

【G3-BM-38】 Q107 · IB Business Management HL · Marketing · Medium

Which pricing strategy involves setting a very low initial price to quickly gain market share?

Answer: B) Penetration pricing. Skimming = high initial price; penetration = low initial price to penetrate the market rapidly and build volume.
【G3-BM-310】 Q108 · IB Business Management HL · Operations Management · Easy

Which production method produces a single, unique product to customer specifications (e.g., custom furniture)?

Answer: A) Job production. Job = one-off custom unit; batch = groups of identical units; flow = continuous standardized units on a line.
【G3-BM-310】 Q109 · IB Business Management HL · Operations · Medium

Which operations management tool identifies the bottleneck activities and critical path of a project?

Answer: C) Critical path analysis. CPA (with network diagrams) calculates EST, LFT, float, and the critical path of tasks determining minimum project duration.
【G3-BM-39】 Q110 · IB Business Management HL · Finance · Easy

Which financial statement shows a firm's assets, liabilities, and equity at a point in time?

Answer: B) Balance sheet. Balance sheet = snapshot of financial position (A = L + E) at a date. Income statement covers a period's revenues and expenses.
【G3-BM-39】 Q111 · IB Business Management HL · Finance · Hard

A company's net profit after tax is $50,000, total equity is $250,000, and it pays $10,000 in dividends. Calculate return on equity (ROE).

Answer: B) 20%. ROE = (Net profit after tax / Equity) × 100% = (50,000 / 250,000) × 100% = 20%. Dividends do not reduce net profit used for ROE.
【G3-BM-37】 Q112 · IB Business Management HL · Human Resource Management · Medium

In Herzberg's two-factor theory, which is a motivating factor (satisfier) rather than a hygiene factor?

Answer: C) Achievement / recognition. Herzberg motivators (intrinsic): achievement, recognition, responsibility, advancement. Hygiene (extrinsic context): pay, conditions, policies—prevent dissatisfaction but do not strongly motivate.
【G3-BM-36】 Q113 · IB Business Management HL · Strategy · Hard

In the BCG matrix, a product with high market share in a low-growth market is classified as a:

Answer: B) Cash cow. BCG: Star = high share, high growth; Cash Cow = high share, low growth (cash-generating mature products); Question mark = low share, high growth; Dog = low share, low growth.
【G3-BM-36】 Q114 · IB Business Management HL · Strategy · Easy

Which Ansoff matrix strategy involves existing products in existing markets?

Answer: C) Market penetration. Ansoff: Penetration = existing product/existing market (lowest risk); Diversification = new product/new market (highest risk).

Computer Science, Psychology, History (6 questions)

【G4-CS-431】 Q115 · IB Computer Science SL · System Fundamentals · Easy

Which of the following best describes an algorithm?

Answer: B) A finite sequence of well-defined steps to solve a problem. Algorithms are unambiguous, have clear inputs/outputs, and terminate (typically).
【G4-CS-434】 Q116 · IB Computer Science HL · Data Structures · Medium

Which data structure uses LIFO (Last-In, First-Out) ordering?

Answer: B) Stack. Push/pop at the top ⇒ LIFO. Queue uses FIFO (First-In, First-Out).
【G4-CS-434】 Q117 · IB Computer Science HL · Algorithms · Hard

Using Big-O notation, what is the average-case time complexity of binary search on a sorted array of size n?

Answer: B) O(log n). Binary search halves the search space each step; number of comparisons is proportional to log₂n ⇒ logarithmic time. Linear search is O(n).
【G3-Hist-313】 Q118 · IB Psychology HL · Criminological / Abnormal · Medium

According to the biological approach to behavior, which brain structure is most associated with the "fight or flight" fear response and emotional memory?

Answer: B) Amygdala. The amygdala (part of the limbic system) is central to fear conditioning, threat appraisal, and forming emotional (fearful) memories.
【G3-Hist-313】 Q119 · IB Psychology HL · Developmental · Medium

Piaget proposed that in the sensorimotor stage, infants develop an understanding that objects continue to exist when out of sight. This concept is called:

Answer: B) Object permanence. A key milestone of the sensorimotor stage (0–2 years), demonstrated typically by 8 months. Conservation appears in the concrete operational stage.
【G3-Hist-312】 Q120 · IB History HL · 20th-Century World History · Easy

Which treaty officially ended World War I and imposed heavy reparations on Germany?

Answer: A) Treaty of Versailles (1919). The Treaty of Versailles (June 1919) redrew Europe, created the League of Nations, and assigned "war guilt" + reparations to Germany, with long-term consequences.