Physics Quiz
Newton, Einstein, refraction and the Doppler effect: 15 questions on how the universe actually works.
Whose three laws of motion were published in the Principia in 1687?
Got a hunch? Pick the answer that feels right.
Isaac Newton
Isaac Newton set out his three laws of motion and his law of universal gravitation in Philosophiae Naturalis Principia Mathematica, published in 1687, laying the foundation of classical mechanics for the next two centuries.
Newton also built the first practical reflecting telescope and shares credit with Gottfried Leibniz for inventing calculus.
What kind of energy does a moving car have because of its motion?
Got a hunch? Pick the answer that feels right.
Kinetic energy
Kinetic energy is the energy of motion, calculated as half the mass times the velocity squared. A stationary car at the top of a hill has potential energy instead, which turns into kinetic energy as it rolls down.
Because the energy rises with the square of speed, a crash at 60 mph releases four times the energy of a crash at 30 mph.
Which effect makes a straw look bent where it enters a glass of water?
Got a hunch? Pick the answer that feels right.
Refraction
Light slows down and changes direction when it passes from air into water, a bending called refraction. Light from the submerged part of the straw reaches your eye from a shifted angle, so the straw appears broken at the surface.
The same bending is why a swimming pool always looks shallower than it really is.
What is the SI unit of energy?
Got a hunch? Pick the answer that feels right.
Joule
The joule, named after English physicist James Prescott Joule, is the work done when a force of one newton moves an object one meter. The watt measures power, the newton measures force and the pascal measures pressure.
Lifting a small apple about one meter (3.3 feet) takes roughly one joule of energy, a handy mental picture of the unit.
What is the approximate acceleration due to gravity at the Earth's surface?
Got a hunch? Pick the answer that feels right.
9.8 meters per second squared
Near the surface, Earth's gravity speeds up a falling object by about 9.8 meters per second every second (32 feet per second squared), ignoring air resistance. That is why a hammer and a feather fall together in a vacuum.
Gravity is slightly weaker at the equator than at the poles because Earth bulges in the middle and spins.
What does an ammeter measure?
Got a hunch? Pick the answer that feels right.
Electric current
An ammeter measures electric current in amperes and is wired in series with the circuit so the whole current flows through it. A voltmeter measures voltage and is connected in parallel instead.
The ampere is named after André-Marie Ampère, the French physicist who founded the science of electrodynamics in the 1820s.
Which color of visible light has the longest wavelength?
Got a hunch? Pick the answer that feels right.
Red
Red light has the longest wavelength humans can see, around 700 nanometers, while violet sits at the short end near 400 nanometers. That is why red always appears on the outer edge of a rainbow.
Beyond red lies infrared, which we feel as heat, and beyond violet lies ultraviolet, which causes sunburn.
Albert Einstein won the 1921 Nobel Prize in Physics for explaining which phenomenon?
Got a hunch? Pick the answer that feels right.
The photoelectric effect
The Nobel committee cited Einstein's explanation of the photoelectric effect, which showed that light arrives in packets of energy called photons, a founding idea of quantum theory. Relativity was still considered too controversial to reward.
His 1905 paper on the photoelectric effect was one of four groundbreaking papers he published that year, now called his miracle year.
Roughly how fast does sound travel through air at room temperature?
Got a hunch? Pick the answer that feels right.
About 343 meters per second
Sound moves through air at about 343 meters per second (1,125 feet per second) at 20 °C, roughly a mile every five seconds. Counting the seconds between a lightning flash and its thunder tells you how far away the storm is.
Sound travels about four times faster in water and around fifteen times faster in steel than it does in air.
According to Archimedes' principle, the upward buoyant force on an object equals the weight of what?
Got a hunch? Pick the answer that feels right.
The fluid the object displaces
Archimedes' principle states that a submerged or floating body is pushed upward by a force equal to the weight of the fluid it pushes aside. A steel ship floats because its hollow hull displaces water that weighs more than the ship.
Legend says Archimedes hit on the idea in the bath and ran through Syracuse shouting Eureka, meaning I have found it.
Which law states that the current through a conductor is proportional to the voltage across it?
Got a hunch? Pick the answer that feels right.
Ohm's law
Ohm's law, written V = IR, links voltage, current and resistance: for a fixed resistance, doubling the voltage doubles the current. The German physicist Georg Ohm published it in 1827.
Hooke's law describes springs, Faraday's law describes electromagnetic induction and Coulomb's law gives the force between electric charges.
What is absolute zero on the Celsius scale?
Got a hunch? Pick the answer that feels right.
About 273 degrees below zero
Absolute zero is minus 273.15 °C (minus 459.67 °F), the point where particles have the lowest possible thermal energy. It is zero on the Kelvin scale that scientists use, so every Kelvin temperature is positive.
Laboratories have cooled atoms to within a few billionths of a degree of absolute zero, but reaching it exactly is impossible.
Which everyday observation is explained by the Doppler effect?
Got a hunch? Pick the answer that feels right.
A siren's pitch drops as an ambulance passes
As a siren approaches, its sound waves are squeezed together, raising the pitch; as it moves away they are stretched out, lowering the pitch. Austrian physicist Christian Doppler described the effect in 1842.
Astronomers use the same effect with light: galaxies moving away show a redshift, which revealed that the universe is expanding.
Which physicist proposed the uncertainty principle in 1927?
Got a hunch? Pick the answer that feels right.
Werner Heisenberg
Heisenberg showed that the position and momentum of a particle cannot both be known with perfect precision at the same time, a fundamental limit built into quantum mechanics rather than a flaw in the instruments.
Heisenberg received the Nobel Prize in Physics for 1932 for creating quantum mechanics, and Schrödinger shared the 1933 prize with Paul Dirac.
Which particle carries the electromagnetic force?
Got a hunch? Pick the answer that feels right.
Photon
In the Standard Model, forces are carried by exchange particles: photons carry electromagnetism, gluons bind quarks through the strong force, and W and Z bosons mediate the weak force. Electrons and neutrinos are matter particles.
Photons have no mass, which is why the electromagnetic force has unlimited range while the weak force acts only across tiny distances.
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All Science quizzes →About the Physics Quiz
Physics explains why a straw looks bent in a glass of water, why a siren drops in pitch as it races past, and why a steel ship floats. Isaac Newton wrote down the laws of motion in 1687, Albert Einstein won his Nobel Prize not for relativity but for the photoelectric effect, and absolute zero sits a chilly 273 degrees below the freezing point of water.
These 15 questions cover forces and energy, light and sound, electricity, and the famous laws and physicists every science student meets. The opening questions are gentle, the middle gets into units and principles, and the last few will test anyone who paid attention in quantum physics class. Perfect for students, pub quiz teams and anyone curious about the world.
You will find 15 multiple choice questions here, each with four options. Difficulty: Medium. Most people finish in about 6 minutes, and every answer comes with a short explanation and one extra fact worth keeping.
How to play
Read the question and pick one of the four answers. The correct answer is revealed straight away with a short explanation, then press Next question to keep going. At the end you get your score out of 15 and a full review of your round. Play again any time and the questions arrive in a fresh order. There is no timer and no account.
Good to know before you play
How hard is this physics quiz?
It is rated Medium. Most questions are school-level physics, with a few harder ones on quantum theory and the Standard Model at the end.
Do I need to do any calculations?
No. Every question can be answered from general physics knowledge, and the explanations supply the numbers and formulas for context.
Which topics does the quiz cover?
Forces and motion, energy, light and sound, electricity, thermodynamics and the scientists behind the big laws, including Newton, Einstein and Heisenberg.
Answer key: all 15 questions with explanations
- Whose three laws of motion were published in the Principia in 1687?
Isaac Newton Isaac Newton set out his three laws of motion and his law of universal gravitation in Philosophiae Naturalis Principia Mathematica, published in 1687, laying the foundation of classical mechanics for the next two centuries. Newton also built the first practical reflecting telescope and shares credit with Gottfried Leibniz for inventing calculus. - What kind of energy does a moving car have because of its motion?
Kinetic energy Kinetic energy is the energy of motion, calculated as half the mass times the velocity squared. A stationary car at the top of a hill has potential energy instead, which turns into kinetic energy as it rolls down. Because the energy rises with the square of speed, a crash at 60 mph releases four times the energy of a crash at 30 mph. - Which effect makes a straw look bent where it enters a glass of water?
Refraction Light slows down and changes direction when it passes from air into water, a bending called refraction. Light from the submerged part of the straw reaches your eye from a shifted angle, so the straw appears broken at the surface. The same bending is why a swimming pool always looks shallower than it really is. - What is the SI unit of energy?
Joule The joule, named after English physicist James Prescott Joule, is the work done when a force of one newton moves an object one meter. The watt measures power, the newton measures force and the pascal measures pressure. Lifting a small apple about one meter (3.3 feet) takes roughly one joule of energy, a handy mental picture of the unit. - What is the approximate acceleration due to gravity at the Earth's surface?
9.8 meters per second squared Near the surface, Earth's gravity speeds up a falling object by about 9.8 meters per second every second (32 feet per second squared), ignoring air resistance. That is why a hammer and a feather fall together in a vacuum. Gravity is slightly weaker at the equator than at the poles because Earth bulges in the middle and spins. - What does an ammeter measure?
Electric current An ammeter measures electric current in amperes and is wired in series with the circuit so the whole current flows through it. A voltmeter measures voltage and is connected in parallel instead. The ampere is named after André-Marie Ampère, the French physicist who founded the science of electrodynamics in the 1820s. - Which color of visible light has the longest wavelength?
Red Red light has the longest wavelength humans can see, around 700 nanometers, while violet sits at the short end near 400 nanometers. That is why red always appears on the outer edge of a rainbow. Beyond red lies infrared, which we feel as heat, and beyond violet lies ultraviolet, which causes sunburn. - Albert Einstein won the 1921 Nobel Prize in Physics for explaining which phenomenon?
The photoelectric effect The Nobel committee cited Einstein's explanation of the photoelectric effect, which showed that light arrives in packets of energy called photons, a founding idea of quantum theory. Relativity was still considered too controversial to reward. His 1905 paper on the photoelectric effect was one of four groundbreaking papers he published that year, now called his miracle year. - Roughly how fast does sound travel through air at room temperature?
About 343 meters per second Sound moves through air at about 343 meters per second (1,125 feet per second) at 20 °C, roughly a mile every five seconds. Counting the seconds between a lightning flash and its thunder tells you how far away the storm is. Sound travels about four times faster in water and around fifteen times faster in steel than it does in air. - According to Archimedes' principle, the upward buoyant force on an object equals the weight of what?
The fluid the object displaces Archimedes' principle states that a submerged or floating body is pushed upward by a force equal to the weight of the fluid it pushes aside. A steel ship floats because its hollow hull displaces water that weighs more than the ship. Legend says Archimedes hit on the idea in the bath and ran through Syracuse shouting Eureka, meaning I have found it. - Which law states that the current through a conductor is proportional to the voltage across it?
Ohm's law Ohm's law, written V = IR, links voltage, current and resistance: for a fixed resistance, doubling the voltage doubles the current. The German physicist Georg Ohm published it in 1827. Hooke's law describes springs, Faraday's law describes electromagnetic induction and Coulomb's law gives the force between electric charges. - What is absolute zero on the Celsius scale?
About 273 degrees below zero Absolute zero is minus 273.15 °C (minus 459.67 °F), the point where particles have the lowest possible thermal energy. It is zero on the Kelvin scale that scientists use, so every Kelvin temperature is positive. Laboratories have cooled atoms to within a few billionths of a degree of absolute zero, but reaching it exactly is impossible. - Which everyday observation is explained by the Doppler effect?
A siren's pitch drops as an ambulance passes As a siren approaches, its sound waves are squeezed together, raising the pitch; as it moves away they are stretched out, lowering the pitch. Austrian physicist Christian Doppler described the effect in 1842. Astronomers use the same effect with light: galaxies moving away show a redshift, which revealed that the universe is expanding. - Which physicist proposed the uncertainty principle in 1927?
Werner Heisenberg Heisenberg showed that the position and momentum of a particle cannot both be known with perfect precision at the same time, a fundamental limit built into quantum mechanics rather than a flaw in the instruments. Heisenberg received the Nobel Prize in Physics for 1932 for creating quantum mechanics, and Schrödinger shared the 1933 prize with Paul Dirac. - Which particle carries the electromagnetic force?
Photon In the Standard Model, forces are carried by exchange particles: photons carry electromagnetism, gluons bind quarks through the strong force, and W and Z bosons mediate the weak force. Electrons and neutrinos are matter particles. Photons have no mass, which is why the electromagnetic force has unlimited range while the weak force acts only across tiny distances.
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