GK Science

Digestion begins in the mouth, where mechanical breakdown by teeth and chemical breakdown by saliva (amylase) start the process.

Electric meters measure the total energy consumed over time, which is expressed in kilowatt-hours (kWh). While watts measure power, the meter records the cumulative energy usage.

Ductility is the ability of a material to be drawn into a thin wire. Gold is widely recognized as the most ductile metal, as a single gram can be drawn into a wire several kilometers long.

A pressure cooker traps steam, which increases the internal pressure. According to the laws of thermodynamics, an increase in pressure raises the boiling point of water, allowing food to cook at a higher temperature.

Pasteurization is a heat treatment process used to kill pathogens in milk. While specific temperatures vary, heating to approximately 63 to 65 degrees Celsius for 30 minutes is a standard method known as Low Temperature Long Time (LTLT) pasteurization.

Centripetal force is defined as the force that acts on a body moving in a circular path and is directed toward the center of the curvature. This inward pull keeps the object from moving in a straight line.

Sir Isaac Newton formulated the Law of Universal Gravitation in his work Principia Mathematica. He described the gravitational force between two masses as proportional to the product of their masses and inversely proportional to the square of the distance between them.

Bleaching is a chemical process that removes color or whitens materials by oxidizing or reducing the pigments. It is commonly used in textiles and paper industries.

The human body is composed primarily of oxygen (approx 65%), followed by carbon (approx 18%), and nitrogen (approx 3%). Therefore, the descending order is oxygen, carbon, nitrogen, which corresponds to 1, 3, 2.

Ball bearings convert sliding friction into rolling friction. Rolling friction is significantly lower than sliding friction, which makes movement easier and reduces wear on the axle.

Mosquitoes act as vectors for various diseases, including malaria (Anopheles) and yellow fever (Aedes). They transmit the pathogens by biting humans and transferring the germs through their saliva.

German silver is a misnomer, as it contains no silver. It is an alloy composed of copper, zinc, and nickel, known for its silvery appearance and corrosion resistance.

The pressure cooker works by increasing the pressure inside the vessel. This increased pressure raises the boiling point of water, allowing the food to be cooked at a higher temperature than it would be in an open pot.

Dew forms when the surface temperature drops below the dew point due to radiative cooling. On cloudy nights, clouds act as a blanket, reflecting thermal radiation back to the surface and preventing the rapid cooling necessary for dew formation.

In a flame test, copper compounds produce a characteristic green color. This is due to the excitation of copper ions in the flame.

Conventional sources of energy are those that have been used for a long time and are generally non-renewable or traditional, such as fossil fuels or large-scale hydroelectric power. Solar, geothermal, and wind are considered non-conventional or renewable sources.

The normal resting heart rate for an adult human typically ranges from 60 to 100 beats per minute. The range 60 to 80 is well within the healthy average.

The Law of Conservation of Energy states that energy cannot be created or destroyed, only transformed from one form to another. This is a fundamental principle of physics.

Dry ice is the solid form of carbon dioxide. It is produced by compressing and cooling gaseous carbon dioxide until it undergoes a phase change into a solid.