Explanation

• CFCs, carbon dioxide (CO₂), and methane (CH₄) are all greenhouse gases.
• Carbon dioxide traps heat in the atmosphere and increases temperature.
• Methane is a very strong greenhouse gas with high warming effect.
• CFCs also damage the ozone layer and act as greenhouse gases.

Last verified on 16-06-2026

Explanation

• Ocean water is not drinkable due to a high amount of sodium chloride (common salt).
• This salt makes water too salty for human consumption.
• Seawater also contains small amounts of other dissolved minerals.
• High salt concentration causes dehydration in the human body.

Last verified on 25-06-2026

Explanation

• A rectifier is an electrical device that converts Alternating Current (AC) into Direct Current (DC).
• It allows current to flow in only one direction.
• It is commonly used in power supplies and chargers.
• Rectifiers use components like diodes for conversion.

Last verified on 25-06-2026

Explanation

• Mass and Length are base quantities in SI units.
• Length SI Unit: meter (m)
• Mass SI Unit: kilogram (kg)

Additional information:

Base Quantities in SI System:

• Time (second)
• Electric current (ampere)
• Temperature (kelvin)

Last verified on 16-06-2026

Explanation

• Electric fire alarms work on the principle of expansion of metals due to heat.
• A fire alarm uses a bimetallic strip that bends when heated because different metals expand at different rates.
• This bending completes an electric circuit and activates the alarm.
• It is an example of the thermal expansion principle.

Last verified on 25-06-2026