In which state of matter are the particles held in fixed positions and only able to vibrate about those positions?
Solid
Liquid
Gas
Plasma
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WhyIn a solid the particles are tightly packed in a regular arrangement and vibrate about fixed positions, giving a solid its fixed shape and volume.
2Multiple choice · Easy
Which state of matter can flow and takes the shape of its container but keeps a fixed volume?
Liquid
Solid
Gas
Crystal
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WhyIn a liquid the particles are close together but can move past one another, so a liquid flows and takes the container shape while keeping a fixed volume.
3Multiple choice · Easy
What is the main method of heat transfer through a metal spoon placed in a hot drink?
Conduction
Convection
Radiation
Evaporation
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WhyHeat travels through solid metals mainly by conduction, where energy is passed along by vibrating particles and free electrons.
4Multiple choice · Easy
Thermal energy from the Sun reaches the Earth through empty space mainly by which process?
Radiation
Conduction
Convection
Condensation
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WhyRadiation is the only method of heat transfer that does not need a medium, so the Sun's energy crosses the vacuum of space by radiation.
5Multiple choice · Easy
What name is given to the change of state from a liquid to a gas that occurs throughout the liquid at a fixed temperature?
Boiling
Melting
Freezing
Condensation
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WhyBoiling is the change from liquid to gas that happens at a fixed temperature (the boiling point) and occurs throughout the whole liquid.
6Multiple choice · Easy
Which surface is the best emitter and absorber of thermal radiation?
A dull black surface
A shiny silver surface
A shiny white surface
A polished mirror
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WhyA dull black surface is the best emitter and best absorber of infrared radiation, whereas shiny silver surfaces are poor emitters and absorbers.
7Fill in the blank · Easy
The random motion of small visible particles such as smoke specks in air, caused by collisions with fast-moving air molecules, is called motion.
Answer:
Brownian / brownian
WhyBrownian motion is the random movement of larger visible particles caused by being struck unevenly by smaller, fast-moving molecules.
8Fill in the blank · Easy
When most substances are heated they expand because the particles gain energy and vibrate more, increasing the average between them.
Answer:
separation / spacing / distance
WhyHeating increases the kinetic energy of particles so they vibrate more vigorously, increasing the average separation and causing expansion.
9Multiple choice · Medium
A gas is sealed in a rigid container and heated. Which statement best explains why the gas pressure increases?
The molecules move faster and collide with the walls more often and more forcefully
The molecules expand in size so there is less empty space
The number of gas molecules increases when heated
The molecules stop moving and press steadily on the walls
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WhyHeating raises the average speed of the molecules, so they hit the walls harder and more often per second, increasing the pressure.
10Multiple choice · Medium
Why does convection occur in fluids but not in solids?
Particles in a fluid can move from place to place, allowing currents to form
Solids cannot absorb any thermal energy
Solids only transfer heat by radiation
Fluids have no particles to carry energy
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WhyConvection relies on warm, less dense fluid rising and cooler fluid sinking; particles in a solid cannot move from place to place, so no convection current can form.
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