Explanation

When a force acts on an object, and the object's displacement is perpendicular to the direction of the force, the work done is zero.

This is because work is calculated as the force component in the direction of displacement multiplied by the displacement.

If the force is perpendicular, that component is zero. 

Explanation

The physical quantity measured in Pascal is Pressure. 

A Pascal (Pa) is the SI unit for pressure, defined as force per unit area (N/m²). 

a) Energy: Energy is measured in Joules (J). 

c) Force: Force is measured in Newtons (N), which is the numerator in the definition of pressure (Pa = N/m²). 

d) Work: Work is also measured in Joules (J), as it is the product of force and distance. 

Explanation

When sunlight hits your skin, your body produces vitamin D.

Specifically,

The UVB radiation from sunlight causes a chemical in the skin to convert to previtamin D3,

Which then turns into vitamin D3.

This process is why vitamin D is often referred to as the "sunshine vitamin." 

Explanation

Carbon dioxide (CO2) reacts with calcium hydroxide (Ca(OH)2.

It is also known as lime water to form a white precipitate of calcium carbonate (CaCO3), which turns the solution milky:

Ca(OH)2 + CO2 → CaCO3 + H2O

This reaction is often used as a test for carbon dioxide.

Explanation

Sodium chloride (NaCl) forms ionic bonds, which are considered the strongest type of bonding in solids.

These bonds involve a strong electrostatic attraction between positively charged sodium ions (Na+) and negatively charged chlorine ions (Cl-).

This results in a stable crystal lattice structure, requiring a significant amount of energy to overcome and melt the compound. 

Explanation

Formic acid is present in the sting of ants.

It causes a sharp, burning sensation and irritation when injected into the skin during an ant sting.

Explanation

Light travels at about 300,000 kilometers per second in a vacuum with a refractive index of 1.0,

but slows down to 225,000 kilometers per second in water

and 200,000 kilometers per second in the glass.

ND16-3-2023

Explanation

Protons: Have a positive charge.

Electrons: Have a negative charge.

Neutrons: Have no charge.

Positrons: A positively charged electron

Explanation

The physical quantity measured in Joules is Work. 

A Joule (J) is the SI unit for measuring energy transferred when a force is applied over a distance, and work is a form of energy. 

a) Power: Power is measured in Watts (W), which are Joules per second (J/s). 

c) Force: Force is measured in Newtons (N). 

d) Velocity: Velocity is measured in meters per second (m/s). 

Explanation

The hormone that lowers blood glucose levels is insulin.

It is produced by the pancreas and works by helping glucose enter cells for energy and signaling the liver

And muscles to store excess glucose as glycogen.

This action prevents blood sugar from becoming too high, keeping it within a healthy range.