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FBISE SSC practice questions

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Question 1Multiple Choice Questions (MCQs)

In the FBISE SSC Physics syllabus, which quantity is defined as the rate of change of displacement with respect to time?

  1. Speed
  2. Acceleration
  3. Velocity Correct answer.
  4. Momentum

Explanation

Velocity is a vector quantity defined as displacement divided by the time taken, so it includes direction as well as magnitude. Acceleration is the rate of change of velocity, and speed ignores direction, so only velocity matches the definition given.

Question 2Multiple Choice Questions (MCQs)

A body moves 6 m east and then 8 m north. What is the magnitude of its resultant displacement?

  1. 10 m Correct answer.
  2. 14 m
  3. 48 m
  4. 2 m

Explanation

The two displacements are perpendicular, so the resultant is found with the Pythagorean relationship: the square root of (6 squared plus 8 squared), which is the square root of 100, giving 10 m. Simple addition would only apply if the motions were along the same straight line.

Question 3Multiple Choice Questions (MCQs)

Which statement correctly describes the chemical bonding in a molecule of carbon dioxide?

  1. It contains two double covalent bonds. Correct answer.
  2. It contains two single covalent bonds.
  3. It contains two ionic bonds.
  4. It contains one double and one single covalent bond.

Explanation

Each oxygen atom shares two pairs of electrons with the central carbon atom, so carbon dioxide has two double covalent bonds and is a linear molecule. The octet rule is satisfied for carbon with four shared pairs in total.

Question 4Multiple Choice Questions (MCQs)

How many moles are present in 36 g of water? (Molar mass of water = 18 g/mol)

  1. 18 mol
  2. 1 mol
  3. 2 mol Correct answer.
  4. 0.5 mol

Explanation

The number of moles equals mass divided by molar mass, so 36 g divided by 18 g/mol gives 2 moles. This is a direct application of the mole relationship used throughout the SSC chemistry course.

Question 5Multiple Choice Questions (MCQs)

Which part of a cell is described as the site of aerobic respiration and ATP production?

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

Explanation

Mitochondria contain the enzymes of the Krebs cycle and the electron transport chain, so most ATP from aerobic respiration is produced there. Ribosomes build proteins, and the Golgi apparatus modifies and packages them.

Question 6Multiple Choice Questions (MCQs)

In a food chain, only about ten per cent of energy passes from one trophic level to the next. Which explanation best accounts for the loss?

  1. Most energy is destroyed when organisms are eaten.
  2. Energy is converted completely into body mass at each level.
  3. Energy is stored permanently in the Sun's radiation.
  4. Energy is lost as heat through respiration and in undigested material. Correct answer.

Explanation

Energy is neither created nor destroyed, but at each trophic level much of it is released as heat during respiration and some passes out in faeces and excretory products. This is why food chains rarely have more than four or five links.

Question 7Multiple Choice Questions (MCQs)

Which of the following is a correct statement about isotopes of an element?

  1. They have the same number of protons but different numbers of neutrons. Correct answer.
  2. They have different atomic numbers and identical mass numbers.
  3. They have the same number of neutrons but different numbers of protons.
  4. They have the same number of electrons in the nucleus.

Explanation

Isotopes are atoms of the same element, so their atomic number and proton count are identical, but their neutron numbers differ, giving different mass numbers. Chemical behaviour is nearly the same because the electron arrangement is unchanged.

Question 8Multiple Choice Questions (MCQs)

A car travelling at 20 m/s decelerates uniformly and stops in 5 s. What is the magnitude of its deceleration?

  1. 100 m/s²
  2. 5 m/s²
  3. 4 m/s² Correct answer.
  4. 0.25 m/s²

Explanation

Acceleration equals change in velocity divided by time, so (0 minus 20) divided by 5 gives minus 4 m/s², meaning a deceleration of 4 m/s². The negative sign simply shows that the acceleration opposes the motion.

Question 9Multiple Choice Questions (MCQs)

Which statement best explains why a metal conducts electricity while a solid ionic compound such as sodium chloride does not?

  1. Delocalised electrons in the metal carry charge, while ions in the solid ionic lattice are fixed in position. Correct answer.
  2. Metals contain mobile protons that carry the current.
  3. Ionic compounds contain no charged particles at all.
  4. Metal ions are free to move through the solid lattice.

Explanation

Conduction requires mobile charge carriers. In a metal, outer electrons are delocalised and move through the lattice; in a solid ionic compound the ions are held in fixed positions and can only conduct when molten or dissolved.

Question 10Multiple Choice Questions (MCQs)

Which process in the water cycle involves water vapour changing directly into liquid droplets in the atmosphere?

  1. Evaporation
  2. Condensation Correct answer.
  3. Sublimation
  4. Transpiration

Explanation

Condensation is the change of state from gas to liquid, and it forms cloud droplets when moist air cools. Evaporation is the reverse change, from liquid to vapour.

Question 11Multiple Choice Questions (MCQs)

Which of the following is a scalar quantity?

  1. Weight
  2. Work Correct answer.
  3. Force
  4. Displacement

Explanation

Work is the product of force and displacement in the direction of the force, and it has magnitude but no direction, so it is a scalar. Force, displacement and weight are all vectors because direction is part of their definition.

Question 12Multiple Choice Questions (MCQs)

An object of weight 60 N is lifted vertically through a height of 3 m. What useful work is done against gravity?

  1. 20 J
  2. 180 J Correct answer.
  3. 63 J
  4. 180 W

Explanation

Work done against gravity equals weight multiplied by vertical height, so 60 N times 3 m gives 180 J. The watt is a unit of power, not of work, so the numerical answer must be expressed in joules.

Question 13Multiple Choice Questions (MCQs)

Which organelle is responsible for absorbing light energy during photosynthesis in a plant cell?

  1. Cell wall
  2. Nucleus
  3. Lysosome
  4. Chloroplast Correct answer.

Explanation

Chloroplasts contain chlorophyll, which absorbs light energy and drives the light-dependent reactions of photosynthesis. The nucleus stores genetic material and does not take part in capturing light.

Question 14Multiple Choice Questions (MCQs)

Which of the following best describes the function of a fuse in a household circuit?

  1. It increases the supply voltage when appliances are switched on.
  2. It melts and breaks the circuit when the current exceeds a safe value. Correct answer.
  3. It converts alternating current into direct current.
  4. It stores electrical energy for later use.

Explanation

A fuse contains a thin wire that overheats and melts if the current rises above its rating, breaking the circuit and preventing fire or damage. It is a safety device, not a voltage regulator or converter.

Question 15Multiple Choice Questions (MCQs)

Which statement about the pH scale is correct?

  1. A solution of pH 9 is acidic.
  2. The pH scale measures the mass of solute in a solution.
  3. A solution of pH 2 is more acidic than a solution of pH 5. Correct answer.
  4. Neutral solutions have a pH of 14.

Explanation

Lower pH values correspond to higher hydrogen ion concentration, so pH 2 is a stronger acid than pH 5. The scale runs from 0 to 14, with 7 being neutral.

Question 16Multiple Choice Questions (MCQs)

Two resistors of 3 ohms and 6 ohms are connected in parallel across a 6 V supply. What is the total current drawn from the supply?

  1. 3 A Correct answer.
  2. 0.67 A
  3. 9 A
  4. 2 A

Explanation

The parallel combination is found from one over R equals one third plus one sixth, giving R equal to 2 ohms. Using Ohm's law, current equals 6 V divided by 2 ohms, which is 3 A.

Question 17Multiple Choice Questions (MCQs)

In a balanced chemical equation, what does the law of conservation of mass require?

  1. The reactants must all be elements rather than compounds.
  2. The products must have a greater total mass than the reactants.
  3. The total mass of reactants equals the total mass of products. Correct answer.
  4. The number of molecules on each side must always be equal.

Explanation

In a closed system, atoms are neither created nor destroyed, so the total mass before and after a reaction is unchanged. Balancing an equation ensures the number of atoms of each element is the same on both sides.

Question 18Multiple Choice Questions (MCQs)

A student observes that a plant kept in darkness for several days loses its starch content. Which conclusion is best supported by this observation?

  1. Chlorophyll is absent from the leaves of the plant.
  2. Starch is produced only when light is available for photosynthesis. Correct answer.
  3. Plants respire only during the night.
  4. Starch is broken down faster in the dark than it is formed.

Explanation

Starch is a storage product of photosynthesis, so a plant deprived of light cannot make it and existing starch is used up. This classic experiment demonstrates that light is essential for photosynthesis.

Question 19Multiple Choice Questions (MCQs)

Which of the following is the correct electronic configuration of a chlorine atom (atomic number 17)?

  1. 2, 7, 8
  2. 2, 8, 7 Correct answer.
  3. 2, 9, 6
  4. 2, 8, 8

Explanation

Electrons fill the shells in order, with a maximum of 2 in the first shell and 8 in the second, leaving 7 in the third shell for chlorine. This gives the configuration 2, 8, 7.

Question 20Multiple Choice Questions (MCQs)

Which statement correctly compares the mass and charge of a proton and an electron?

  1. A proton has no charge while an electron is negatively charged.
  2. An electron is heavier than a proton and carries a negative charge.
  3. A proton is heavier than an electron and carries a positive charge. Correct answer.
  4. A proton and an electron have equal mass but opposite charges.

Explanation

A proton has a relative mass of about 1 and a charge of plus one, whereas an electron has a relative mass of about one eighteen-hundredth and a charge of minus one. The proton is therefore far heavier.

Question 21Multiple Choice Questions (MCQs)

A body moves in a circle at constant speed. Which statement about its motion is correct?

  1. Its velocity is constant because its speed is constant.
  2. Its acceleration is zero because the speed is unchanged.
  3. It moves in a straight line with uniform acceleration.
  4. Its velocity changes because its direction changes continuously. Correct answer.

Explanation

Velocity is a vector, so a change in direction at constant speed still means a changing velocity. This produces a centripetal acceleration directed towards the centre of the circle.

Question 22Multiple Choice Questions (MCQs)

Which of the following is the main function of the root hair cells in a plant?

  1. To carry out photosynthesis for the root
  2. To store chlorophyll for the plant
  3. To transport food from the leaves to the roots
  4. To absorb water and mineral salts from the soil Correct answer.

Explanation

Root hair cells have a long, thin extension that increases the surface area for absorbing water by osmosis and mineral ions by active transport. They are not photosynthetic and do not transport food downwards.

Question 23Multiple Choice Questions (MCQs)

A solution contains 10 g of sodium chloride dissolved in 90 g of water. What is the percentage by mass of sodium chloride in the solution?

  1. 11.1 per cent
  2. 9 per cent
  3. 90 per cent
  4. 10 per cent Correct answer.

Explanation

Percentage by mass equals the mass of solute divided by the total mass of solution, multiplied by 100. Here 10 g divided by 100 g gives 0.1, which is 10 per cent.

Question 24Multiple Choice Questions (MCQs)

Which statement best explains why the melting point of magnesium oxide is much higher than that of sodium chloride?

  1. Magnesium oxide contains free electrons in the solid state.
  2. Sodium chloride is held together by weak van der Waals forces.
  3. Magnesium oxide has a giant covalent structure.
  4. Magnesium oxide has ions of higher charge, so stronger electrostatic attractions hold the lattice together. Correct answer.

Explanation

Both compounds are ionic, but magnesium and oxide ions carry double charges compared with sodium and chloride ions, so the electrostatic attraction in the lattice is much stronger. More energy is therefore needed to break the lattice and melt the solid.

Question 25Multiple Choice Questions (MCQs)

A transformer has 200 turns in its primary coil and 50 turns in its secondary coil. If the primary voltage is 240 V, what is the secondary voltage?

  1. 60 V Correct answer.
  2. 480 V
  3. 960 V
  4. 120 V

Explanation

For an ideal transformer the voltage ratio equals the turns ratio, so the secondary voltage is 240 V multiplied by 50 and divided by 200, giving 60 V. This is a step-down transformer because the secondary has fewer turns.

Question 26Multiple Choice Questions (MCQs)

Which quantity is obtained by multiplying a body's mass by its velocity?

  1. Acceleration
  2. Momentum Correct answer.
  3. Power
  4. Weight

Explanation

Momentum is defined as the product of mass and velocity, p = mv, and it is a vector quantity measured in kg m/s. The other quantities are defined differently: acceleration is rate of change of velocity, weight is mass times gravitational field strength, and power is rate of doing work.

Question 27Multiple Choice Questions (MCQs)

In the SI system, which base unit is used to express the amount of a substance?

  1. Mole Correct answer.
  2. Kelvin
  3. Candela
  4. Kilogram

Explanation

The mole is the SI base unit for amount of substance and contains the Avogadro number of particles. The kilogram measures mass, the kelvin measures thermodynamic temperature, and the candela measures luminous intensity.

Question 28Multiple Choice Questions (MCQs)

Which structure of the human eye changes its shape to focus light from objects at different distances?

  1. Retina
  2. Cornea
  3. Lens Correct answer.
  4. Iris

Explanation

The lens alters its curvature through the action of the ciliary muscles, a process called accommodation, so that a sharp image falls on the retina for both near and distant objects. The cornea provides most of the fixed refraction, while the retina detects the image and the iris controls pupil size.

Question 29Multiple Choice Questions (MCQs)

Which gas is released at the cathode when dilute sulphuric acid is electrolysed using inert electrodes?

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

Explanation

At the cathode, reduction occurs and hydrogen ions gain electrons to form hydrogen gas, so hydrogen is liberated there. Oxygen is produced at the anode from the discharge of hydroxide ions, and chlorine is not present in dilute sulphuric acid.

Question 30Multiple Choice Questions (MCQs)

Which part of a flowering plant develops into the fruit after fertilisation?

  1. Stigma
  2. Ovule
  3. Ovary Correct answer.
  4. Anther

Explanation

After fertilisation the ovary wall thickens and the ovary becomes the fruit, while the ovules inside develop into seeds. The stigma is part of the female receptive surface, and the anther produces pollen grains.

Question 31Multiple Choice Questions (MCQs)

Which statement describes the arrangement of particles in a solid?

  1. Particles are widely spaced and held by strong attractive forces.
  2. Particles are far apart and move randomly at high speed.
  3. Particles are closely packed in fixed positions and vibrate about those positions. Correct answer.
  4. Particles are closely packed but slide freely past one another.

Explanation

In a solid the particles are held close together in a regular lattice by strong forces, and they can only vibrate about fixed mean positions. This restricted motion explains the fixed shape and volume of solids.

Question 32Multiple Choice Questions (MCQs)

Which of the following is a renewable source of energy?

  1. Natural gas
  2. Coal
  3. Wind Correct answer.
  4. Diesel

Explanation

Wind is replenished continuously by solar heating of the atmosphere, so it is renewable and does not run out on a human timescale. Natural gas, coal, and diesel are fossil fuels formed over millions of years and are being consumed faster than they form.

Question 33Multiple Choice Questions (MCQs)

Which statement about the number of protons in an atom of an element is correct?

  1. It is called the mass number of the element.
  2. It changes when the element forms a compound.
  3. It is called the atomic number and is fixed for that element. Correct answer.
  4. It equals the number of neutrons in every atom of that element.

Explanation

The number of protons is the atomic number, and it is the same for every atom of a given element, which is what defines the element. The mass number instead counts protons plus neutrons, and the proton count does not change in chemical reactions.

Question 34Multiple Choice Questions (MCQs)

A 4 kg block is pulled along a rough horizontal floor by a horizontal force of 30 N while a friction force of 10 N acts on it. What is the acceleration of the block?

  1. 2.5 m/s²
  2. 10 m/s²
  3. 5 m/s² Correct answer.
  4. 7.5 m/s²

Explanation

The resultant horizontal force is 30 N minus 10 N, which is 20 N. Applying Newton's second law, a = F/m = 20 N ÷ 4 kg = 5 m/s² in the direction of the applied force.

Question 35Multiple Choice Questions (MCQs)

A wave has a frequency of 50 Hz and a wavelength of 4 m. What is its speed, and how far does it travel in 0.2 s?

  1. 0.08 m/s and 0.016 m
  2. 200 m/s and 40 m Correct answer.
  3. 54 m/s and 10.8 m
  4. 12.5 m/s and 2.5 m

Explanation

Wave speed equals frequency multiplied by wavelength, so v = 50 Hz × 4 m = 200 m/s. The distance travelled is speed multiplied by time, giving 200 m/s × 0.2 s = 40 m.

Question 36Multiple Choice Questions (MCQs)

Which change would increase the rate of a chemical reaction between marble chips and dilute hydrochloric acid?

  1. Diluting the acid with water
  2. Increasing the volume of the container
  3. Using smaller chips of the same total mass Correct answer.
  4. Cooling the reaction mixture

Explanation

Smaller chips expose a larger surface area for the same mass of marble, so collisions with acid particles occur more frequently and the rate increases. Dilution and cooling both reduce collision frequency, while container volume has no direct effect here.

Question 37Multiple Choice Questions (MCQs)

Which statement about a neutralisation reaction is correct?

  1. An acid reacts with a base to produce a salt and water. Correct answer.
  2. An acid reacts with a metal to produce a salt and hydrogen.
  3. An acid reacts with a carbonate to produce a salt and water only.
  4. A base reacts with a metal to produce hydrogen gas.

Explanation

Neutralisation is the reaction between an acid and a base, producing a salt and water as the hydrogen ions and hydroxide ions combine. Reactions of acids with metals and with carbonates are different types of reaction with different products.

Question 38Multiple Choice Questions (MCQs)

A cell of electromotive force 3 V drives a current of 0.5 A through a resistor. What is the power dissipated in the resistor?

  1. 0.17 W
  2. 6 W
  3. 1.5 W Correct answer.
  4. 3.5 W

Explanation

Electrical power is the product of voltage and current, so P = V × I = 3 V × 0.5 A = 1.5 W. The same result follows from P = I²R, since the resistance here is 6 ohms.

Question 39Multiple Choice Questions (MCQs)

Which statement correctly explains why the pressure of a fixed mass of gas increases when it is heated at constant volume?

  1. The gas molecules become larger and occupy more space.
  2. The gas molecules collide with the walls more often and with greater force. Correct answer.
  3. The attractive forces between gas molecules increase with temperature.
  4. The number of gas molecules increases as the gas is heated.

Explanation

At constant volume, heating raises the average kinetic energy of the molecules, so they strike the container walls more frequently and with greater momentum change per collision, raising the pressure. The number and size of the molecules do not change.

Question 40Multiple Choice Questions (MCQs)

Which statement best describes the role of the placenta in a mammalian pregnancy?

  1. It mixes maternal and fetal blood so that they share the same composition.
  2. It stores food for the embryo until birth.
  3. It produces the amniotic fluid that surrounds the embryo.
  4. It allows exchange of nutrients, oxygen, and waste between maternal and fetal blood. Correct answer.

Explanation

The placenta brings the fetal and maternal blood close together so that substances such as oxygen and glucose diffuse to the fetus while carbon dioxide and urea diffuse away. The two blood supplies do not mix directly, which protects the fetus from many harmful substances and from different blood groups.

Question 41Multiple Choice Questions (MCQs)

Which of the following is the most direct cause of variation among offspring produced by sexual reproduction?

  1. Mitosis in body cells
  2. Fusion of gametes carrying different combinations of genes Correct answer.
  3. Formation of identical gametes in every parent
  4. Replication of DNA before cell division

Explanation

Sexual reproduction brings together gametes that carry different allele combinations, and their random fusion produces offspring with new gene combinations. Mitosis and DNA replication produce genetically identical copies, so they do not themselves create this variation.

Question 42Multiple Choice Questions (MCQs)

Which statement about the reactivity of Group I metals is correct?

  1. Reactivity increases down the group because the outer electron is lost more readily. Correct answer.
  2. Reactivity increases down the group because the atoms gain electrons more easily.
  3. Reactivity decreases down the group because the atoms become smaller.
  4. Reactivity stays the same down the group because all have one outer electron.

Explanation

Down Group I the atoms get larger and the outer electron is further from the nucleus and shielded by more inner shells, so it is lost more easily. Metals lose electrons in reactions, so this makes the elements more reactive down the group.

Question 43Multiple Choice Questions (MCQs)

Why is a step-down transformer used in the transmission of electrical energy over long distances?

  1. It decreases the voltage so that the current in the cables increases.
  2. It stores energy in the cables so that it can be released later.
  3. It increases the voltage so that the current and the heating losses in the cables are reduced. Correct answer.
  4. It converts alternating current into direct current for the cables.

Explanation

For a given power, raising the transmission voltage lowers the current, and since power lost as heat in the cables equals I²R, the losses fall sharply. Transformers work only with alternating current and do not store energy.

Question 44Multiple Choice Questions (MCQs)

A ray of light passes from air into glass of refractive index 1.5 at an angle of incidence of 30°. Which statement about the refracted ray is correct?

  1. It bends towards the normal and the angle of refraction is less than 30°. Correct answer.
  2. It is totally internally reflected back into the air.
  3. It bends away from the normal and the angle of refraction is greater than 30°.
  4. It travels along the normal because the angle of refraction is zero.

Explanation

When light enters a denser medium it slows down and bends towards the normal, so the angle of refraction is smaller than the angle of incidence. Applying Snell's law gives sin r = sin 30° ÷ 1.5, so r is about 19.5°.

Question 45Multiple Choice Questions (MCQs)

Which statement correctly describes the difference between an ionic bond and a covalent bond?

  1. Ionic bonds form only between non-metals, while covalent bonds form only between metals.
  2. Both types of bonding involve transfer of electrons, but only ionic bonds form between non-metals.
  3. Ionic bonding involves transfer of electrons, while covalent bonding involves sharing of electrons. Correct answer.
  4. Ionic bonding involves sharing of electrons, while covalent bonding involves transfer of electrons.

Explanation

In ionic bonding, electrons are transferred from a metal atom to a non-metal atom, creating oppositely charged ions held by electrostatic attraction. In covalent bonding, non-metal atoms share pairs of electrons so that both achieve stable outer shells.

Question 46Multiple Choice Questions (MCQs)

An ideal gas is compressed at constant temperature to half its original volume. Which statement about the gas is correct?

  1. Its pressure quadruples because the volume is reduced fourfold.
  2. Its pressure stays the same because temperature is constant.
  3. Its pressure halves because the molecules move more slowly.
  4. Its pressure doubles because the molecules collide with the walls twice as often per unit area. Correct answer.

Explanation

At constant temperature the average kinetic energy of the molecules is unchanged, but halving the volume doubles the number of molecules per unit volume. The collision frequency with the walls per unit area therefore doubles, so the pressure doubles, in line with Boyle's law.

Question 47Multiple Choice Questions (MCQs)

A 2 kg object moving at 6 m/s collides with a stationary 4 kg object, and the two stick together. What is their common velocity immediately after the collision?

  1. 1 m/s
  2. 4 m/s
  3. 2 m/s Correct answer.
  4. 3 m/s

Explanation

Momentum is conserved in the collision, so the total momentum before impact, 2 kg × 6 m/s = 12 kg m/s, equals the total momentum after. The combined mass is 6 kg, giving a common velocity of 12 ÷ 6 = 2 m/s.

Question 48Multiple Choice Questions (MCQs)

Which observation best supports the conclusion that a chemical reaction has reached equilibrium?

  1. All the reactants have been used up and only products remain.
  2. The rate of the forward reaction is greater than the rate of the reverse reaction.
  3. The reaction has stopped completely, and no particles are moving.
  4. The concentrations of reactants and products remain constant while both forward and reverse reactions continue. Correct answer.

Explanation

At dynamic equilibrium the forward and reverse reactions proceed at equal rates, so the concentrations of all substances stay constant even though both reactions continue. The system is not static, and neither reaction has stopped.

Question 49Multiple Choice Questions (MCQs)

In a cross between two heterozygous pea plants for seed shape, where round (R) is dominant to wrinkled (r), what is the expected ratio of round to wrinkled seeds in the offspring?

  1. 1:2:1
  2. 3:1 Correct answer.
  3. 1:1
  4. 9:3:3:1

Explanation

A cross of Rr with Rr gives the genotypes RR, Rr, Rr, and rr, so three of the four outcomes show the dominant round phenotype. The expected phenotypic ratio of round to wrinkled is therefore 3:1.

Question 50Multiple Choice Questions (MCQs)

A sample of a radioactive isotope has a half-life of 8 days. What fraction of the original nuclei remains after 32 days?

  1. 1/4
  2. 1/8
  3. 1/32
  4. 1/16 Correct answer.

Explanation

Thirty-two days is four half-lives, since 32 ÷ 8 = 4. Each half-life halves the remaining nuclei, so the fraction left is (1/2)⁴, which equals 1/16.