Physics questions This is a list of recently added questions about physics. Play physics quiz and see all the questions. What is dry ice?Solidified CO2. Dry ice is used in refrigeration. It has an interesting property: it maintains a constant temperature of -78.5C in a warmer environment. This is because dry ice does not melt and sublimes directly into the gaseous form.Created by: Niezgodnaice riddles »very easy 92% glacierglacier309solidified CO2solidified CO28417legendary alchemical substancelegendary alchemical substance224meringue dessertmeringue dessert149 Imagine that a distant civilization watches the Earth from 100 million light years away. What can they see right now?Dinosaurs. If a distant civilization watches the Earth right now, it sees its image from the past.Created by: Krzysztof Moskalastronomy riddles »hard 53% skyscrapersskyscrapers208the future the future 688dinosaursdinosaurs2852early Earth with no life yetearly Earth with no life yet1577 How many hydrogen isotopes occur naturally on the Earth?Three isotopes of hydrogen occur naturally on the Earth: the most frequent protium (1H), deuterium (2H) and tritium (3H). Other isotopes of hydrogen (4H-7H) were created in laboratories and are highly unstable.Created by: Paweł Kołodziejczykelements riddles »hard 58% oneone791twotwo1208threethree3367fourfour395 What is the unit of the conductance?1S (siemens). Conductance (conductivity) is the reverse of the resistance. So it is a measure of the susceptibility of the element to the flow of the electric current. Siemens is the unit of electric conductance named after German inventor and industrialist Werner von Siemens, founder of the well known Siemens company.Created by: Paweł Kołodziejczykelectricity riddles »very hard 39% 1Ω (ohm)1Ω (ohm)5041S (siemens)1S (siemens)9801H (henry)1H (henry)3331T (tesla)1T (tesla)637 Who invented the mercury-in-glass thermometer?Gabriel Daniel Fahrenheit. Daniel Gabriel Fahrenheit was a German physicist, engineer, and glass blower who is best known for inventing the mercury-in-glass thermometer (1714), and for developing a temperature scale now named after him Created by: Paweł Kołodziejczykinventors riddles »very hard 34% Galileo GalileiGalileo Galilei520Anders CelsiusAnders Celsius699Gabriel Daniel FahrenheitGabriel Daniel Fahrenheit801William KelvinWilliam Kelvin314 In what temperatures is the superconductivity observed?Very low. Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields, which occur in certain materials when cooled below a characteristic critical temperature. This quantum phenomenon is impossible to be explained by the classical physics. Created by: Paweł Kołodziejczyktechnology riddles »hard 46% very lowvery low1531very highvery high479in every temperaturein every temperature185it depends on the material usedit depends on the material used1114 What does "FM" found on radio receivers stand for?Frequency Modulation. In telecommunications and signal processing, frequency modulation (FM) is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave. Created by: Paweł Kołodziejczykmusic riddles »hard 46% Amplitude ModulationAmplitude Modulation189Frequency ModulationFrequency Modulation2297Fast ModulationFast Modulation947Microwaves Microwaves 1471 What is "c" in E=mc^2?Speed of light. In words, energy equals mass multiplied by the speed of light squared.Created by: Paweł Kołodziejczykdiscoverers riddles »easy 70% thermodynamic free energythermodynamic free energy361specific heat capacityspecific heat capacity472speed of lightspeed of light2511Coulomb, unit of the electric chargeCoulomb, unit of the electric charge208 Which of the hydrogen isotopes is radioactive?Tritium. The two lightest isotopes of hydrogen are stable (protium and the heavy hydrogen (deuterium)). The tritium is radioactive and unstable, with half-life of 12.32 years. It is the only radiocative isotope of hydrogen which naturally occurs on Earth (although it is extremely rare). Created by: Paweł Kołodziejczyknames riddles »hard 56% ProtiumProtium462DeuteriumDeuterium1434TritiumTritium4225NoneNone1390 How are the laws concerning the flow of the current in forks of the electric circuit called?Kirchhoff's circuit laws. Kirchhoff's current law is also called Kirchhoff's first law, Kirchhoff's point rule, or Kirchhoff's junction rule (or nodal rule). The principle of conservation of electric charge implies that: At any node (junction) in an electrical circuit, the sum of currents flowing into that node is equal to the sum of currents flowing out of that node or equivalently The algebraic sum of currents in a network of conductors meeting at a point is zero. Created by: Paweł Kołodziejczyktechnology riddles »hard 57% Ampère's circuit lawsAmpère's circuit laws795Kirchhoff's circuit lawsKirchhoff's circuit laws3189Faraday's circuit lawsFaraday's circuit laws642Ohm's circuit lawsOhm's circuit laws910 Play physics quiz and see all the questions.