Question

Lidia plans an experimental investigation to see how the thickness of a lens affects the point where a beam of light is focused. She plans to shine light through a lens and measure the distance to a screen that is placed where the beam focuses.
What are the controls in Lidia’s investigation?

the material and thickness of the lens
the type of light and the material of the lens
the distance to the screen and the type of light
the thickness of the lens and the distance to the screen

Answer 1

Answer:

Option B

the type of light and the material of the lens

Explanation:

Since the experiment focuses on investigating how thickness of a lens affects the point where a beam of light, it means thickness of lens here are indepedent variable since Lydia has control over the thickness and can alter it. However, the point where beam of light focuses on is depedent variable since Lydia will just observe the point but can't change it. To ensure that other external factors don't affect the results, Lydia has to ensure that the type of material irrespective of thickness remain constant and also the source of light must be kept constant. Therefore, the controls will be the type of light and the material of the lens