Explanation

Ball bearing reduces friction by using smooth balls lubricated with oil or grease

that freely roll between a smooth inner and outer surface.

SH5-8-2023

Explanation

In solar furnaces, concave mirrors are used for converging the sun's rays.

concept:

Concave mirrors reflect and focus incoming light rays (parallel) at a point, called the focus point.

Depending on the distance of an object from the reflecting surface, different types of images are formed.

Explanation

Pyridine is an important class of nitrogen-containing heterocycles found in various natural products.

Explanation

Copper, silver and gold are the three metals that are used for making coins and are called coinage metals

Explanation

Convex lenses are used to treat presbyopia, hypermetropia, and aphakia

hypermetropia, and hyperopia, is a condition of the eye where distant objects are seen clearly but near objects appear blurred.

Explanation

Joseph Priestly discovered oxygen on August 1, 1774.

The most abundant element in the Earth's crust is oxygen, making up 46.6% of Earth's mass

Explanation

Joseph Priestly discovered oxygen on August 1, 1774.

The most abundant element in the Earth's crust is oxygen, making up 46.6% of Earth's mass

Explanation

By mole fraction (i.e., by variety of molecules), dry air contains seventy eight.08% element, 20.95% oxygen, 0.93% argon, 0.04% greenhouse emission, and tiny amounts of alternative gases

Explanation

A galvanometer is an instrument that can detect and measure small amounts of current in an electrical circuit

Explanation

A gemstone is used to make jewelry or other adornments.