Physics

A gas pycnometer is a laboratory device used for measuring the density — or more accurately the volume — of solids, be they regularly shaped, porous or non-porous, monolithic, powdered, granular or in some way comminuted, employing some method of gas displacement and the volume-pressure relationship known as Boyle’s Law. A gas pycnometer is also sometimes referred to as a helium pycnometer. While pycnometer (of any type) is recognized as density measuring devices they are in fact devices for measuring volume only.

A mirage is a naturally occurring optical illusion or phenomenon in which light rays are bent due to refraction in layers of air of varying density. The image usually is upside down, enhancing the illusion that the sky image seen in the distance is really a water or oil puddle acting as a mirror.

The speed of an object in a particular direction is called velocity.

Radio waves have the longest wavelength, and gamma rays have the shortest wavelength.

The interval between object pass the same point is 4 sec._x000D_ That means in 2 sec, object reaches the top and in next 2 sec, it again reaches the same point._x000D_ By the info given, we can find the velocity of that point by using : v=u+(-gt)_x000D_ 0= u – 10×2_x000D_ u = 20_x000D_ Then the velocity at 25m is 20m/sec._x000D_ so the initial velocity is_x000D_ −v = u + (−2gh)_x000D_ 400 = u − 2x 10 x 25_x000D_ u = 900_x000D_ => u = 30 m/s

The Zener diode is like a general-purpose signal diode. When based in the forward direction it behaves just like a normal signal diode, but when a reverse voltage is applied to it, the voltage remains constant for a wide range of currents and hence widely used for regulated electric supply. The device was named after Clarence Zener, who discovered this electrical property. Many diodes described as “Zener” diodes rely instead on avalanche breakdown as the mechanism. Common applications include providing a reference voltage for voltage regulators, or to protect other semiconductor devices from momentary voltage pulses. Zener diodes are widely used as voltage references and as shunt regulators to regulate the voltage across small circuits.

Two thin shirts can keep us warmer than a single thick shirt in winter because of the air that is trapped between the two thin shirts. This air acts as an insulator and ensures that heat does not escape.