Science Physics Topics Flashcards

Why do we see lightning before we hear thunder?

Answer: Light travels faster than sound

Light travels at about 300,000 km/s, much faster than sound at about 340 m/s. So we see the flash before we hear the boom.

What is the purpose of the earth wire in a three-pin plug?

Answer: To provide a safe path for current in case of a fault

The earth wire provides a low-resistance path to the ground. If a fault occurs, current flows through the earth wire instead of through a person.

Which of the following changes requires the absorption of heat?

Answer: Melting

Melting (solid to liquid) requires heat energy to be absorbed to break the bonds holding particles in a solid structure.

What happens to the pitch of a sound when the frequency increases?

Answer: The pitch gets higher

Pitch and frequency are directly related. Higher frequency vibrations produce higher-pitched sounds.

Which colour of light is refracted the most when white light passes through a prism?

Answer: Violet

Violet light has the shortest wavelength and is refracted (bent) the most. Red light has the longest wavelength and is refracted the least.

What energy transformation occurs in a solar panel?

Answer: Light to electrical

Solar panels convert light energy from the Sun into electrical energy using photovoltaic cells.