Explanation

U − B contains all elements in the universal set U that are not in B, which is called the complement of B.

The standard notation for the complement of a set is B′.

Last verified on 16-03-2026

Explanation

Sales tax = 7% of 1500 = 0.07 × 1500 = Rs. 105

Total cost = 1500 + 105 = Rs. 1605

Last verified on 16-03-2026

Explanation

• Sand is primarily composed of silicon dioxide (SiO₂).
• It is a chemical compound made of silicon and oxygen atoms in a 1:2 ratio.
• SiO₂ is found in quartz, glass, and sand naturally.
• It is hard, chemically stable, and insoluble in water.

Last verified on 16-03-2026

Explanation

• Temperature is a physical quantity because it can be measured directly using a thermometer.
• It describes how hot or cold a body is without changing its chemical composition.
• Physical quantities are measurable properties like length, mass, volume, and temperature.
• Weight, force, and speed are derived quantities because they depend on mass, acceleration, or distance.

Last verified on 16-03-2026

Explanation

• Dilution refers to the process of decreasing the concentration of a solution by adding more solvent.
• While ionisation involves the formation of ions from molecules in a solution.

Last verified on 16-03-2026

Explanation

• Citric acid is a natural preservative found in many fruits, particularly in citrus fruits like lemons, oranges, and grapefruits.
• It's responsible for their sour taste and is also used as a food additive.
• Other fruits like mangoes, grapes, and strawberries also contain citric acid, although in smaller amounts.
• The presence of citric acid gives these fruits their characteristic sour taste.

Last verified on 16-03-2026

Explanation

• When light is focused in front of the retina, it creates a blurred image, indicating nearsightedness (myopia).
• This occurs because the eyeball is too long or the cornea is too steep.
• It causing light to focus before reaching the retina.

Last verified on 16-03-2026

Explanation

KE = 0.5mv² = 0.5 × 0.25 kg × (20 m/s)² = 0.5 × 0.25 × 400 = 50 J

Last verified on 16-03-2026

Explanation

The renewable energy sources are:

• Water energy
• Wind energy
• Tidal energy
• Solar energy
• Hydroelectric
• Ocean energy
• Geothermal energy
• Biomass
• Biogas

The non-renewable energy sources are:

• Fossil fuels or Hydrocarbon fuel (Oil, Natural gas, Coal)
• Nuclear energy

Last verified on 16-03-2026

Explanation

• Gear is a wheel with teeth along its edge that interlock with another gear to transmit motion and force.
• Gears are used to increase or decrease speed, change direction, or increase torque in machines.
• Common in clocks, bicycles, vehicles, and industrial machines.

Last verified on 16-03-2026