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There is a so-called "Universal Indicator" that contains a mixture of thymol blue, methyl red, bromothymol blue and phenolphthalein. The aim is to make an indicator that changes colour progressively through the range pH4 to pH14. They supply a colour chart to read off the correct pH value, but...

Phew ... where to start? In the limited time you have remaining, you must make sure you have revised these topics and have prepared answers to typical questions: (1) AS1100 drawing standards - transforming orthogonal to pictorial, and vice versa. Assembly drawings, sectioned drawings, drawing...

Mathematics Advanced or Mathematics Extension 1 would be quite adequate for HSC Physics. In my experience, you have to distinguish between students who have two types of mathematical ability. There are students who are good at crunching formulae and numbers (which I call formulaic maths) and...

Yes, that answer sheet must be wrong. Frequency never changes when a light wave passes between two different mediums. Think of it this way: Crests and troughs are arriving at the interface. (i) If the frequency is going to increase on the other side of the interface, where are these extra crests...

Short Answer: all of it is important. The more you can retain, the better off you will be. However, some content is definitely more important than others. Vectors, kinematics, dynamics and electromagnetism are absolutely vital. Waves and thermodynamics are less important. After Year 11, you...

I remember a classic geometric proof of this inequality. I like this proof because it is easy to grasp, and elegant. As a couple of others have said, it is closely related to the arithmetic mean/geometric mean inequality. I also offer a second, more conventional, algebraic proof that relies on...

Exam technique. Draw a graph of what you expect the velocity of the skydiver to look like. Transfer any data that is provided onto the graph. Then think about acceleration as the derivative of velocity with respect to time, ie. acceleration is the slope of the velocity versus time graph. Then...

You are right. All you can conclude is that cathode rays transmit energy, but whether they are particles or waves is impossible to say. Crookes incorrectly attributed the motion of the paddle wheel to momentum transfer from his cathode rays. About 20 years later, J J Thompson (using his new...

HSC students will never be required to recall the value of the Hubble Constant Ho (current value 70 kilometres per second per megaparsec). However, students are required to know what it means, and how it was first derived. If any data is required to answer a question related to the Hubble...

Yes, the use of the same symbol "d" can be a bit confusing for students. When we analyse the diffraction pattern produced by a single slit, then d is the symbol given to the width of the slit. As light passes through a single slit, it creates a single bright band accompanied by diffraction...

Rather than re-state the definitions of the fundamental SI units that are readily available on the Internet, I would refer interested students to this article from the United States National Institute of Standards and Technology, about the reason for the change in 2019...

The question is examining Module 5 Equilibrium and Acid Reactions, and in particular, solution equilibrium and dynamic equilibrium. The initial solution is saturated, no more solid can dissolve, so IV is wrong. The added mass of the radioactive solid will increase the total solids, so III is...

I think you are referring to combustion of Mg, which gives a very bright white light. No, the white light from burning Mg in oxygen is not a line spectrum. It is a continuous spectrum given off by the hot particles of MgO, which emit a broad continuous spectrum. The characteristic line emission...

Surfactant is short for "surface active agent". There are two ways to answer your question. We can cite experimental evidence, or we can give the theory. I will give some evidence. Soaps and detergents concentrate at interfaces as a mono-molecular layer. For example, their presence in the...

Well spotted! Thanks.

For Question 8, the velocity of the charged particle, I get, v = Bqr/m = (0.1 x 1.6E-16 x 0.1)/6.692E-27) = 2.391 x 10^8 m/s , and this is option (C). Check my maths, please!

The relativistic momentum argument is the best line to take in the HSC syllabus. Perhaps there is another way to argue that "C" is a cosmic speed limit, because "C" is the maximum speed of causality. Any two objects that are travelling at a relative speed greater than "C" cannot be part of the...

The question is examining Hubble's relation between red-shift, velocity of recession and distance. This relation holds true for large distances, but within the local group, it is not true. There are galaxies like M31, the Andromeda galaxy and the Large Magellanic Cloud, which are part of our...

Hertz was a skilled builder of his own experimental apparatus, and a perfectionist. At the age of just 31, and armed with the theory of Maxwell, Hertz set out to be the first person to prove if electromagnetic energy could be generated by accelerating electric charges [yes]. The energy could...

Physical Chemistry isn't really a syllabus topic. There isn't really an equation, because it's not a chemical change, it's a physical change. The industrial process for the manufacture of pure liquid oxygen and liquid nitrogen starts with liquid air, which contains 20% O2 and 79% N2 and about 1%...