Explanation

When dilute acids react with many metals, they produce hydrogen gas.

For example:

2HCl + Zn → ZnCl2 + H2.

Explanation

When acids react with carbonates, they produce carbon dioxide gas, water, and a salt.

For example:

2HCl + Na2CO3 → 2NaCl + H2O + CO2.

Explanation

Sodium hydroxide (NaOH) is a strong electrolyte because it completely dissociates into ions in water.

It conducts electricity well.

It is used in many industrial processes.

Explanation

Non-electrolytes are substances that do not dissociate into ions in solution, so they do not conduct electricity.

Examples include sugar and pure water.

Explanation

Sodium carbonate (Na₂CO₃) is commonly known as soda ash.

It is used in glass making, detergents, and water softening.

Explanation

• When an electron jumps from a higher energy level to a lower energy level, it radiates energy.
• The electron releases this excess energy in the form of a photon (electromagnetic radiation) as it moves to a more stable, lower-energy state. 
•  Lower-Radiates/Emits energy.
• Lower- Higher: Absorbs energy. 

Last updated question by NA on 28 April 2026

Explanation

When light passes from a rarer to a denser medium, its speed and wavelength decrease, but the frequency stays the same.

This is because the source determines frequency, and it doesn’t change with medium.

Explanation

Gauss → Unit of magnetic induction (CGS system)

Tesla → SI unit of magnetic induction

Weber/Ampere·meter → This is a unit of magnetic permeability, not magnetic induction

Explanation

Using the formula for parallel resistance: 1/R_eq = 1/R1 + 1/R2

1/24 = 1/40 + 1/R

Solving for R gives R = 60Ω.

Explanation