Terminal Velocity - A Level Physics

When an object comes down under gravity in the air, it is subjected at least two forces, the weight - W  -  and the drag / air resistance - R.  The resultant force, F = W - R F = ma  W - R = ma, where m and a are the mass of the object and the drag respectively. As the object comes down, the drag, goes …

Read more »

Stellar Parallax for A Level Physics - astrophysics

Parallax is an optical phenomenon when the apparent position of an an object changes with the position of the observer. In order to experience this, you can hold the your index finger some distance from your right eye - or left eye, depending on your convenience - and then moving your head slowly to…

Read more »

Basic Calculus - differentiation for beginners IGCSE, AS, A-Level

The process of finding the gradient or slope of a function is the differentiation. We used to find the gradient of a straight line, just by dividing the change in 'y' by change in 'x', in a certain range of values. When it comes to a curve, however, it is not easy to find the gradien…

Read more »

Galilean Telescope

The Galilean Telescope was invented by the legendary Italian physicist, Galileo Galilei in 1609. It is a simple telescope consisting of a convex lens and a concave lens; they act as the objective and eyepiece respectively. With the aid of his invention, Galileo managed to look at  J upiter’s four large…

Read more »

Galileo Galilei in a Jigsaw Puzzle - interactive play

The above jigsaw puzzle is of a famous physicist who was born in the month of February. He was instrumental in turning the astronomy upside down with his discoveries and theories despite being at odds with a powerful religious establishment at that time. You can find out who he is by playing with th…

Read more »

Transformation of Graphs - stretching

The tranformations of graphs are aimed at: GCSE IGCSE GCE -OL GCE - AL AS A Level High School T he above animation shows the strtching of a graph parallel to y-axis and x-axis. f(x) → af(x) is stretching parallel to y-axis by a factor a. E.g. f(x) = x² - 2x → 2f(x) = 2(x² - 2x) f(x) → f(ax) is stretching parall…

Read more »

Root-Mean-Square Voltage - r-m-s voltage of AC

The root-mean-square value of a function, f(t), is calculated as follows: Integrate the square of the function in the given range of the variable - from a to b in this case. Find the mean value of the above integral, dividing by the range of the variable - (b - a) in this case. Find the square root of…

Read more »

Transformation of Graphs - reflection

The above animation shows the reflection of graphs. It is as follows: f(x) → f(-x) is a reflection in the y-axis f(x) → -f(x) is a reflection in the x-axis E.g. f(x) = x 2 - 2x f(-x) = (-x) 2 - 2(-x) = x 2 + 2x -f(x) = -(x 2 - 2x) = - x 2 + 2x

Read more »

Cassegrain Reflector

Cassegrain reflector consists of a concave mirror, convex mirror and an eyepiece. Parallel light from celestial objects enters the telescope. The large concave mirror, the primary reflector, is used to collect the light and bring it to a focus.  A secondary reflector, the convex reflector, is used to…

Read more »

Transformation of Graphs - translation

f(x) → f(x + a) - a translation in the negative x-axis by a f(x) → f(x - a) - a translation in the positive x-axis by a f(x) → f(x) +  a - a translation in the positive y-axis by a f(x) → f(x) -  a - a translation in the negative y-axis by a E.g.1 Sketch y = x 2 + 2x - 3 and find the following: The line o…

Read more »

Phase Difference between Two Points on a Wave and Path Difference Explained - interactive

In the above animation, five points on the wave are considered for the explanation.  The fully interactive applet is given below for you to practise. The phase of a point implies its direction of vibration on a wave. For example, both points A and E vibrate exactly the same way are said to be in phas…

Read more »

Terrestrial Telescope - refracting telescope explained with interactive animation

The above animation is a terrestrial telescope, a refracting telescope. It has evolved from another refracting telescope, the astronomical telescope that produces an inverted image, making it not suitable for viewing objects on the Earth. The terrestrial telescope has addressed the issue to some ext…

Read more »