Explanation

• The lightning conductor or rod used for protecting buildings from lightning is made of copper.
• A lightning conductor is a metal rod installed at the highest point of a building to provide a safe path for lightning current to reach the ground.
• Copper is commonly used.
• Because it is an excellent electrical conductor.
• It has good resistance to corrosion.

Additional information:

• Light rod was invented by Benjamin Franklin in the 18th century.

Last verified on 21-10-2026

Explanation

• Australia is located in the Southern Hemisphere, where summer begins around December.
• During December, the Southern Hemisphere tilts towards the Sun because of Earth’s axial tilt of approximately 23.5°.

Additional information:

• Australia’s summer generally lasts from December to February, while winter lasts from June to August.

Last verified on 21-10-2026

Explanation

• When the brake shoe or brake pad presses against a rotating drum or disc, friction is produced.
• This friction converts the tractor’s kinetic energy into heat energy, slowing down or stopping the wheels.
• Brake effectiveness depends on the friction between the braking surfaces and the condition of the brake components.

Last verified on 16-10-2026

Explanation

• Saturated vapour exists at the saturation temperature corresponding to a given pressure.
• During boiling, liquid water changes into steam at its saturation temperature, provided the pressure remains constant.
• At standard atmospheric pressure, water boils at approximately 100°C, and its saturation pressure is approximately 101.325 kPa.

Last verified on 16-10-2026

Explanation

• The number of spark plugs needed in a diesel engine is zero
• Diesel engines use compression ignition instead of a spark.
• Air is compressed until it is hot enough to ignite the fuel.
• Instead of spark plugs, they use glow plugs to warm the engine when cold

Explanation

• A change of 1 Kelvin (K) is equal in magnitude to a change of 1 degree Celsius (°C).
• Therefore, a rise of 10 K equals a rise of 10°C.
• The numerical values of Kelvin and Celsius differ when expressing an actual temperature, but their temperature intervals are equal.

Last verified on 16-10-2026

Explanation

• Strain is the ratio of the change in length to the original length of a material when a force is applied.
• It measures the relative deformation of a material.
• It has no unit, because it is a ratio of two lengths.

Last verified on 16-10-2026

Explanation

• Surface tension decreases as temperature increases.
• Higher temperature increases the kinetic energy of liquid molecules, weakening the effect of intermolecular cohesive forces at the surface.
• Surface tension becomes nearly zero at the critical temperature, where the distinction between liquid and gas disappears.
• Water has a surface tension of approximately 72.8 mN/m at 20°C.

Last verified on 16-10-2026

Explanation

• Nitrogen (N₂) → 78%

Additional information:

• Oxygen (O₂) → 21%
• Argon (Ar) → 0.93%
• Carbon dioxide (CO₂) → 0.04% (approximately)
• Other gases → Trace amounts

Last verified on 28-06-2026

Explanation

• Gamma rays have the highest frequency, shortest wavelength, and highest photon energy.
• They have strong penetrating ability and can pass through many materials.

Additional information:

Electromagnetic Spectrum (High to Low Frequency):

1. Gamma rays
2. X-rays
3. Ultraviolet rays
4. Visible light
5. Infrared rays
6. Microwaves
7. Radio waves

Last verified on 15-10-2026