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Cliff has a bag of tennis balls. 8 are green, 7 are yellow and 5 are white. He picks a tennis ball at random. What is the probability that he picks one that is not green?

To solve this question, we need to know how many balls there are altogether in Cliff's bag. In total, there are 20 balls (8+7+5). We know that 8 of the balls are greens, so by subtraction (20-8) we can tell ...
KS
Answered by Kabilan S. • Maths tutor
5616 Views

An electron is trapped within a square well potential of width 10 nm. What would be the wavelength of the photon emitted when an electron moves from the first energy level to the ground level.

Use energy difference between ground and first level to find E1-E0. Energy of the electron a nth energy level is found using En = (n^2 pi^2 hbar^2)/2mL^2Where n is the energy level plus 1, pi and hbar are co...
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Answered by Aubin G. • Physics tutor
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The diameter of a ring is 19mm. Calculate the area of the ring in cm^2, giving the area to 3 significant figures.

First you must convert the diameter into cm from mm:19/10 = 1.9cmThen you must find the radius of the ring:radius = diameter/2 = 1.9/2 = 0.95 cmThen you can calculate the area:area = 2πr 2 = 2 x π x (0.95) 2...
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Answered by Mary P. • Maths tutor
3901 Views

How do I write a Psychology 12 Mark Question?

When writing a 12 mark answer in Psychology, I find it is most helpful to first understand the Assessment Objectives. In these types of question, you are awarded marks for AO1 (content) and A03 (evaluation)....
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Answered by Rhea S. • Psychology tutor
14057 Views

Find the integral of the following equation: y = cos^2(x)

First convert y into a suitably form.cos(2x) = 1 - 2cos 2 (x)cos 2 x = (1-cos(2x))/2 integral of y = integral of (1-cos(2x))/2 = (1/2)*(x-(1/2)sin(2x)) + C = x/2 - sin(2x)/4 + C
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Answered by Marc H. • Maths tutor
4503 Views