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What is an electron volt?

Electron volts, like joules, are a unit of energy. This may sound confusing- why two? But think of it this way; length has two possible units- metric (metres) and imperial (inches). We can use either units t...
NM
Answered by Nicholas M. • Physics tutor
26314 Views

z = 3x + 5y, if x = 7 and z = 41, what is 2y?

z = 3x + 5y 41 = 3(7) +5y 41= 21 + 5y 20 = 5y 4 = y y = 4 2y = 8
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Answered by Hannah A. • Maths tutor
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How would you correctly carry out a flame test, and what colour would potassium yield, and what colour would lithium yield?

Answer First a wire loop is cleaned with diluted hydrochloric acid, which is then dipped into the sample metal or solution. This is then held over an open flame and the colour emitted is observed. The colour...
CK
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How can I solve quadratic equations by completing the square?

When we have a quadratic (ax 2 + bx + c = 0) we can "complete the square" to solve for x. For example x 2 + 8x + 7 = 0. First look at the x 2 + 8x, in particular the coefficient of x, "b"...
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Answered by Thomas B. • Maths tutor
4204 Views

How do I build up and retain a sufficient level of vocabulary?

The need to build up a sufficient level of vocabulary and retain it is extremely important when taking on the written and oral componants of the A level exams both when it comes to to comprehension and expre...
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Answered by Joshua E. • French tutor
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