Work, Energy & Power

Introduction Much scientific invention has been directed towards designing machines that are beneficial to everyday life. For example, the invention of automobiles completely transformed society. In order for automobiles to work for us, they need to be powerful and energy efficient. Work, energy, power and efficiency are important terms in analysing the performance of machines. … Read more

Stress & Strain

Introduction Ever wondered why, when iron rod can withstand more load, things made of glass or wood breaks easily? The answer lies in behaviour of materials to external loading. This article discusses some of the important properties of the materials that are used to study the effect of when an external load is applied to … Read more

Young’s Modulus

Introduction Young’s modulus is a numerical constant, named after the 18th-century English physician and physicist Thomas Young. Young’s modulus is a measure of the ability of a material to withstand changes in length under lengthwise tension or compression. Young’s modulus is also termed the modulus of elasticity. A. Young’s modulus Most materials under small strain … Read more

Circuits

In this article, the fundamentals of electric charge, current, potential difference, resistance and conservation of charge are discussed. Electric Charge Matter is made up of tiny particles called atoms. An atom consists of protons, neutrons and electrons. Normally, the number of protons and electrons are equal and the overall charge of an atom is zero. … Read more

Potential Divider

A potential divider is widely used in circuits. It is based on the principle that the potential drop across a segment of a wire of uniform cross-section carrying a constant current is directly proportional to its length. It is used in the volume control knob of music systems.  Sensory circuits using light-dependent resistors and thermistors … Read more

Resistivity

A. Resistance All materials resist the flow of charges. The charges accelerate from one point of a circuit to another due to the potential difference between the two points. As the charges move from the negative to the positive terminals, they collide with the positive ions, which get in their way. Some of the kinetic … Read more

Current, Charge & Potential Difference

A. Charge Matter is made of tiny particles called atoms. An atom consists of protons, neutrons and electrons. Normally, the number of protons and electrons are equal and the overall charge of an atom is zero. But, for certain atoms, electrons in the outer shell of an atom can be easily removed. An atom with … Read more

Energy & Power In Circuits

A. Electrical Power Consider the circuit shown below: The battery gives the charges potential energy. In the bulb, electrical energy is transferred to thermal energy and then radiated. The battery supplies 5 J of energy every second, so its power is 5 watts. The bulb is taking energy at the same rate, so its power … Read more

Conservation Of Energy

Introduction Consider a scenario: When diesel is burned in a truck engine, some of the chemical energy stored in the form of liquid is converted into kinetic energy of the truck and some are wasted as thermal energy. When the truck stops, its kinetic energy is converted into internal energy in the brakes. The temperature … Read more

Moments

Introduction When a force acts on an object, the force may cause an object to move in a straight line. It could also cause the object to spin or turn. This turning effect of a force is called the moment of the force. It is defined as the product of the force and the perpendicular … Read more