BTEC Applied Science Unit 5 physics exam with 100% correct answers 2023

What are the standard units of mass, length and time? - Correct answer-Kilograms, metres and seconds What are the SI prefixes for 10^3, 10^6 and 10^9? - Correct answer-kilo, mega, giga What are the SI prefixes for 10^-3, 10^-6 and 10^-9? - Correct answer-milli, micro, nano What is work done? - Correct answer-The energy transferred in moving something What is power? - Correct answer-the rate at which work is done What happens to a gas when it is compressed? - Correct answer-Particles get closer together Gas pressure increases More collisions between particles and container Temperature of gas rises How do you calculate work done from a P-V graph? - Correct answer-The area under the graph What is efficiency? - Correct answer-the percentage of the work input that becomes useful work output What is thermal equilibrium? - Correct answer-when two objects have the same temperatures and net heat transfer is zero What is the first law of thermodynamics? - Correct answer-The change in a system's internal energy is equal to the difference between heat added to the system from its surroundings and work done by the system on its surroundings What are ideal gases? - Correct answer-All collisions are elastic All motion is random There are no forces between particles What is absolute zero? - Correct answer-0 K Particles have 0 kinetic energy What is the second law of thermodynamics? - Correct answer-Heat will not flow from a colder body to a hotter one without an input of work. A natural process cannot fully be reversed. What is an isothermal process? - Correct answer-a process that occurs at constant temperature What is an adiabatic process? - Correct answer-no thermal energy is transferred between the system and its surroundings. What is the Carnot cycle? - Correct answer-an idealised engine cycle What is a heat pump? - Correct answer-Gas goes into the compressor. The compressor squashes the gas to make it hot. The condenser converts the gas into a liquid. The potential energy lost by the particles is released as heat. The expansion valve slows down and spreads out the liquid, like an aerosol, which cools it down The evaporator takes in energy from the surroundings to evaporate the liquid back to a gas. Define specific latent heat. - Correct answer-the energy required to change the state of unit mass of the substance without change of temperature. Define specific heat capacity - Correct answer-energy (in kJ) required to heat one kg of substance by one kelvin How do you find the density of an irregular solid? - Correct answer-Measure mass using balance. Measure volume by looking at amount of water displaced. Mass / volume. Define Hooke's Law - Correct answer-The extension of a spring is directly proportional to the force applied What is the elastic limit? - Correct answer-The maximum amount a material can be stretched by a force without permanently deforming Give examples of malleable and brittle materials - Correct answer-Malleable - layers of atoms able to slide eg copper Brittle - fracture under stress due to layers of atoms eg glass. Define stress - Correct answer-the force per unit area applied to a material Define strain - Correct answer-the ratio of the extension of a material compared to the original length Explain how rubber behaves when it is stressed. - Correct answer-Initially hard to stretch, then strain increases, then before it breaks becomes more difficult to stretch again because the bonds are all stretched out What is elastic hysteresis? - Correct answer-A property where strain lags behind stress when the material is loaded and then unloaded.