Light Energy
How does light travel from one place to another?
Light travels in straight lines from the source.
It reflects off objects in straight lines as well.
What are the three main ways heat energy can be transferred?
Conduction, convection, and radiation.
How does heat travel from the Sun to Earth?
Heat travels from the Sun to Earth through radiation.
What is a series circuit?
A series circuit is a circuit where components are connected in a single path.
What is reflection, and where do we see it in everyday life?
Reflection is the bouncing back of light; seen in mirrors.
What is a light source? Give an example.
A light source is an object that emits light, e.g., the Sun.
How does conduction transfer heat energy? Give an example.
Conduction transfers heat through direct contact, e.g., a metal spoon in hot soup.
Why does warm air rise while cool air sinks?
Warm air is less dense than cool air, causing it to rise.
How is a parallel circuit different from a series circuit?
A parallel circuit has multiple paths for current to flow.
What happens to light when it reflects off a mirror?
It bounces back at the same angle it hit the mirror.
What happens to light when it hits an object?
It can be reflected, absorbed, or transmitted.
What is an insulator, and how does it affect heat transfer?
An insulator is a material that slows down heat transfer, e.g., rubber.
How does the process of heat transfer differ between solids, liquids, and gases?
Solids transfer heat mainly through conduction, liquids through convection, and gases through both.
Why are parallel circuits more common in homes?
Parallel circuits allow devices to operate independently.
What is refraction, and why does it happen?
Refraction is the bending of light as it passes through different media.
How can light be reflected, absorbed, or transmitted?
Light can bounce off surfaces (reflection), be taken in (absorption), or pass through (transmission).
What is radiation, and how does it transfer heat?
Radiation transfers heat through electromagnetic waves, e.g., heat from the Sun.
Why are ovens often designed with metal interiors?
Metal reflects heat and helps distribute it evenly.
How does the current behave differently in series and parallel circuits?
In series, current is the same; in parallel, it divides among branches.
Why does a straw look bent when placed in a glass of water?
The bending is due to refraction of light as it moves from air to water.
Why does light travel slower in water than in air?
Light travels slower in water due to the higher density of water compared to air.
How does convection work, and where do you see it in nature?
Convection transfers heat through the movement of fluids; seen in boiling water.
What is the role of thermal conductivity in heat transfer?
Thermal conductivity measures how well a material conducts heat.
What happens to the total resistance in a series circuit?
Total resistance increases as more components are added.
How does light change speed as it moves from air to water?
Light slows down as it enters water from air.