Explanation

• A barcode reader, also called a price scanner or point-of-sale (POS) scanner.
• It is a hand-held or stationary input device.
• It used to capture and read information contained in a barcode.

Explanation

The SI unit of force is the Newton, symbol N.

The base units relevant to force are:

1. The metre, unit of length — symbol m
2. The kilogram, unit of mass — symbol kg
3. The second, unit of time — symbol s

Explanation

Water has maximum density at 4-degree celsius

while 

When Water is in its Solid form (Ice) below 0 C

Explanation

The Central Nervous System (CNS) comprises the:

• Brain, which processes information.
• The spinal cord, which relays messages between the brain and the body.
• The nerves, which transmit signals throughout the body.

Explanation

The atmospheric pressure at any place is measured by a Barometer

***

The barometer was invented by Evangelista in 1644.

**

Explanation

• The greenhouse effect is an environmental problem caused by the increasing amount of carbon dioxide (CO2) in the atmosphere.
• Primarily due to human activities such as burning fossil fuels, deforestation, and land-use changes.
• This excess CO2 traps heat and leads to global warming and climate change.

Explanation

When white light passes through a prism, it splits into 7 colors, forming a spectrum known as a rainbow:

1. Red
2. Orange
3. Yellow
4. Green
5. Blue
6. Indigo
7. Violet

The separation of visible light into its different colours is known as dispersion.

Explanation

• Short-sightedness (myopia) can be corrected by wearing a concave lens.
• It is thinner in the center than at the edges.
• This lens disperses light rays, allowing them to focus correctly on the retina.

Explanation

• The electricity from a cell (such as a battery) is Direct Current (DC).
• It is the flow of electric charge in one direction only, without changing direction.
• This is the type of current used in electronic devices such as smartphones, laptops, and televisions.

Explanation

• Ozone gas is a molecule made up of three oxygen atoms, with the chemical formula O3.
• This is different from ordinary oxygen, which has the chemical formula O2.