Physics

­A barometer measures air pressure: A “rising” barometer indicates increas­ing air pressure; a “falling” barometer indicates decreasing air pressure.

Blue is the complementary colour of yellow.

Nuclear fusion, the source of all the energy so generously radiated by the Sun, does two things: it converts hydrogen into helium (or rather, makes helium nuclei from protons) and it converts mass to energy.

Rotatory motion is turning round in a circle, such as a wheel turning. While the wheel is moving, the mechanism transfers translatory motion into rotatory motion. As a matter of fact, translatory motion and rotatory motion occur at the same time.

A wheel barrow is an example of second class lever as the load is between the fulcrum and effort,hence it is a second class lever.

While ascending a hill Gear Ratio should be “Either equal to or greater than 1. Gear Ratio is the ratio between angular velocity of input gear to the angular velocity of output gear. It prevents the vehicle from stalling.

An AC meter calibrated to accurately read RMS voltage or current on a pure sine wave will not give the proper value while indicating the magnitude of anything other than a perfect sine wave. This includes triangle waves, square waves, or any kind of distorted sine wave.

The First Law of Thermodynamics states that heat is a form of energy, and thermodynamic processes are therefore subject to the principle of conservation of energy. This means that heat energy cannot be created or destroyed.

The primary reason why the colour red is used for danger signals is that red light is scattered the least by air molecules. The effect of scattering is inversely related to the fourth power of the wavelength of a colour. Therefore blue which has the least wavelength of all the visible radiations is scattered the most and red which has the highest wavelength of all the colours we can see is scattered the least. So red light is able to travel the longest distance through fog, rain, and the alike. Also, red is a colour we inherently perceive as one that is associated with danger.