Tag: science & technology

In Java, this() is used to call one constructor from another constructor in the same class. It must be the first statement in the constructor body. 'this' alone refers to the current object instance, while 'super' and 'super()' are used for parent class references and constructors respectively.

J.J. Thomson discovered the electron in 1897 through his groundbreaking cathode ray tube experiments at Cambridge University. He showed that cathode rays were negatively charged particles much smaller than atoms, which he called 'corpuscles' (later named electrons). This discovery revolutionized our understanding of atomic structure.

Tantalum has the highest boiling point (approximately 5,458°C or 9,856°F) among the given options. This refractory metal is extremely heat-resistant, making it valuable for high-temperature applications like jet engine components and nuclear reactors. Diamond is not an element but pure carbon, platinum melts at a lower temperature, and titanium also has a lower boiling point.

Apples belong to the Rosaceae family, commonly known as the rose family. This large plant family includes not only roses but also many other fruits like pears, cherries, peaches, plums, strawberries, and almonds. The family name Rosaceae comes from the type genus Rosa (roses), which apples are botanically related to.

A manometer is an instrument used to measure pressure, particularly gas or liquid pressure. Saccharimeter measures sugar concentration, ammeter measures electric current, and lactometer measures milk purity. Manometers are essential in various scientific and industrial applications.

A light year is a unit of distance, not time or speed. It represents the distance light travels in one vacuum year (about 9.46 trillion kilometers). Astronomers use it to measure vast interstellar and intergalactic distances.

The joule is the SI unit of energy, defined as the work done when a force of one newton moves an object one meter in the direction of the force. It is used for all forms of energy including kinetic, potential, thermal, and electrical energy.

One gram weight (gram-force) equals 981 dynes under standard gravity (g = 981 cm/s²). The dyne is the CGS unit of force. This conversion is based on the relationship: 1 gram-force = g × 1 gram = 981 cm/s² × 1 g = 981 g·cm/s² = 981 dynes.