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Describe how emission spectra are formed and how they can be used to identify the elemental composition of a star.

Electrons are bound to a nucleus in quantised energy levels. As they gain and lose energy they transition between this energy levels by emitting photons. Emitted photons have energies equal to the change in ...
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Answered by George P. • Physics tutor
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Explain Newton’s law of Gravitation

Newton’s law of gravitation states that the force of attraction between two objects due to their masses is proportional to the product of the two objects and inversely proportional to the distance between th...
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Answered by Mingyuan S. • Physics tutor
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A typical question is about energy transfer - Explain the process of convection and give an example of where we can find them

Molecules in the air encounter an energy source, they gain energy and begin to heat up which causes them to vibrate faster and become less dense which causes them to rise. As they rise, they begin to lose en...
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Answered by Max M. • Physics tutor
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You are sitting in a boat on a lake, you have with you in the boat a large rock. You throw the rock out of the boat and it sinks to the bottom of the lake, does the water level of the lake go up, down or stay the same?

Whilst in the boat the rock (and you) are floating, this means that the amount of water displaced by the rock is the mass of the rock. When the rock sinks to the bottom of the lake the amount of water displa...
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Answered by Jonathan B. • Physics tutor
10613 Views

What is the difference between electromotive force and potential difference?

The electromotive force and the potential difference in a circuit are very similar concepts as they are both names for energy per unit charge within a circuit and they both use the same unit, Volts. The diff...
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Answered by Caillan L. • Physics tutor
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