the amount of light reaching a given surface area in a period of time

oscillations/ripples in electric and magnetic fields

variables are inversely proportional when one increases and the other decreases at the same (proportional) rate, e.g. as one variable doubles, the other variable halves

light intensity is inversely proportional to the square of the distance from the light source

Light intensity and the inverse square law

Combined science

Pupils learned about ways in which the human body maintains a constant internal environment in response to internal and external change, including changes in temperature and water balance.

This unit explores factors affecting photosynthesis rates and focuses on planning and conducting experiments. It includes selecting techniques, accurate measurements, data analysis, and evaluating methods to improve reliability and suggest further investigations.

Photosynthesis: factors affecting the rate

higher light intensity decreases the rate of photosynthesis

higher light intensity increases the rate of photosynthesis

light intensity has no effect on photosynthesis

the effect of light intensity varies with plant species

In what way does light intensity affect the rate of photosynthesis in plants?

the rate increases with light intensity up to a point, then plateaus

the rate decreases as light intensity increases

light intensity has no effect on the rate of photosynthesis

the rate increases indefinitely with increasing light intensity

What is the relationship between light intensity and the rate of photosynthesis?

because light energy is absorbed by the air

because the power of the light source decreases

because the same amount of light is spread over a larger area

Why does light intensity decrease as the distance from the light source increases?

the intensity of light is directly proportional to the distance from the source

the intensity of light increases with the square of the distance

the intensity of light remains constant regardless of distance

the intensity of light is inversely proportional to the square of the distance

What would happen to the light intensity if the distance from the light source is tripled?

rate is directly proportional to the distance from the light source

rate is inversely proportional to the distance from the light source

rate is not related to the distance from the light source

What is the relationship between the rate of photosynthesis and the distance from a light source?

it transfers the energy needed for the reactions of photosynthesis 

it cools the plant during the photosynthesis process

it increases the absorption of carbon dioxide

What is the role of light in photosynthesis?

{{}} is a pigment in plant cells that absorbs light energy, primarily from the sun, to drive the process of photosynthesis.

both variables increase and decrease independently

there is no relationship between the variables

when one variable increases, the other decreases

when one variable increases, the other increases at a constant rate

What does it mean for two variables to be proportional?

What is the primary source of light for photosynthesis?

Which factor is most likely to be a limiting factor of photosynthesis at night?

This lesson will be removed by end of Summer Term 2025.

Light intensity and the inverse square law

Lesson outcome

This lesson will be removed by end of Summer Term 2025.