So gold has 79 protons. This is why it is 79 x 1.6x10^-19 . The plus was there to say that there was that many protons. When dealing with Nuclei of an atom it is always the number of protons which is the charge. This is the same with the specific charge of a nucleus. Hope this helps. Good luck if you exams tomorrow

Since it is a curved surface the the maxima and minima are not at the same position relative to the angle. Normally the first minima will be at n = 0.5 but on a curved surface it is n = 1.22 for the 1st minima Since the gap in the slit spacing is 2 x diameter of the atom the radius = 0.61 Hence the formula R = 0.61sintheta(min) Where the angle is of the 1st minima Hope this helps and good luck with exams if you have any tomorrow!

Yes unfortunately. Though only aspects will be assessed However you break it into sections Definitions of an ideal gas Momentum change of a particle as it hits the wall The impulse and thus force and thus pressure from that change in momentum Apply for all atoms in one direction Apply for all atoms in all direction Find the average speed of the molecules in all directions ( RMS) The most common are definitions of an ideal gas and the momentum change ones Hope this helps and good luck if you have any exams

​@@TLPhysicsthank you 🙏🙏 the papers tommorow

Hi So in reality the earth is a radial gravitational field. g changes the further you are from the surface We can find that with the formula g = GM/r^2 However the change of g from the surface of the earth to mount Everest is tiny. 9.81 at surface and 9.773 at mount Everest. (almost the same 0.4% difference) So we can use mgh as an approximation as g is relatively constant. However the Karman line (100km above the surface) is the space boundary where g is 9.51. Which though similar is now a 3% difference so using mgh would not yield a good value. In fact it would be too large hence we do not use it. I do recommend to watch the videos on field strength to help with it. Hope this helps

Hi because for the elastic potential it is an average force over the distance. The idea is that when you start the stretch it has a tension when you put a weight on it extends this extension increases the tension in the spring. Until the tension in the spring= weight you put on it ( equilibrium) So the potential energy energy is caused by a tension that changes over that extension distance which is why we need to take an average. Mathematically (ignoring constants) ∫F dx = Fx = energy F in elastic potential = Kx so ∫Kx dx = 0.5Kx^2 = 0.5Fx (since F = Kx) Hope that helps.

Hi So energy and mass are related. If you took 0.511Mev convert it into joules ( by multiplying by 1.6 x 10 ^-19 ) you would have the same(ish) value as if you used e=mc^2 with the mass of the electron. I should have used rest mass energy specifically. But good spot.

Hi It depends where you count your starting point. If you count zero as the point of release after it has been displaced then amplitude ( displacement from equilibrium) starts as max. While if you count the start when you are at equilibrium it is sin. Aqa uses cos Hope that's helps

Hi So the mass of the earth that is causing the force of attraction towards the centre of the earth is the mass that is below you. On the surface it you are affected by the whole planet If you went underground the mass of the earth beneath you pulling you down would be less ( and the radius to the centre is less) as some will be above you. This is why the relationship is different. Mathematically g =GM/r^2 After the surface of the earth all is constant ( including M) so you have the inverse square law. However if you imagine the earth is constant density so for a sphere = M/(4/3 x pi x r^3) So M = density x 4/3 x pi x r^3 So g = (G x density x 4/3 x pi x r ^3) / r^ 2 Which simplifies to g = G x density x pi x r So g is directly proportional to r which is why is it a straight line. Hope it helps.

Hi Physics is physics so yes however please be aware ocr may have slightly different definitions on key terms so please check the specification. Hope this helps

Hi Yes the spec has not changed since 2015. Hope this helps

Hi Physics is the same however always check any definitions along side your specification to make sure you get the key words correctly. Hope that helps

It is an estimation of the lines that are in the diffraction grating. It could be 200 or 400 but that would be a different grating entirely

Hi It was in the video before the on the playlist here kzbin.info/www/bejne/h6XcqaljosqDe8k Hope that helps!

Hi no, but you will find it should be about 1.something x 10^-15 in your answers. If you are not given it in an exam you will need to calculate it to find it. But you can assume it is constant between calculations Hope that helps

Hi In closest approach yes! The more energy ( thus potential) the alpha particle has the closer it will get.

No, it just helps and it means you can use the graph too!