Explanation

The least distance of distinct vision for a normal human eye is 25 cm.

This means that when an object is placed at a distance of 25 cm or more from the eye, a clear and distinct image is formed on the retina. 

Explanation

Simple harmonic motion (SHM) is also known as oscillatory motion or periodic motion.

It can also be referred to as harmonic oscillation.

It is a system exhibiting SHM that is often called a simple harmonic oscillator. 

Explanation

In semiconductors, when an electron leaves its position in the valence band, it creates a "hole" which can act as a positive charge carrier.

This is why holes are primarily associated with semiconductors. 

Explanation

Polar orbiting satellites travel over the Earth from pole to pole and are mainly used for collecting weather and climate data.

They provide detailed global coverage, useful for forecasting and environmental monitoring.

Explanation

In most automobiles, only about 10%–15% of the chemical energy in gasoline is converted into mechanical energy to move the car.

The rest is lost as heat, friction, and through the exhaust system.

Explanation

In deep space far from massive objects, the gravitational pull becomes negligible, effectively making gravity zero.

This is why astronauts experience weightlessness in such regions.

Explanation

Nuclear energy is released when the nucleus of an atom is split (fission) by a slow-moving neutron.

This process is used in nuclear reactors and atomic bombs to produce large amounts of energy.

Explanation

In a gas meter, gears are connected to the wheel mechanisms to accurately transfer and display the volume of gas consumed.

These gears rotate the dials based on the gas flow, providing precise readings.

Explanation

At a radio station, a person speaks into a microphone, which converts sound waves into electrical signals.

These signals are then processed and transmitted through an antenna to reach listeners.

Explanation

Sputnik-2, launched by the Soviet Union on 3rd November 1957, weighed approximately 508 kilograms.

It carried Laika, the first living creature (a dog) to orbit Earth.