3.2.3a Converging and diverging lenses

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Question 11

A student investigates how the concentration of a salt solution inside a hollow, double-convex lens affects its focal length.

The focal length $f$ of the lens is given by the equation:

\frac{uv}{u+v}

where $u$ is the distance between the illuminated object and the lens, and $v$ is the distance between the lens and the sharp image formed on a screen.

Plan an experiment to investigate how the concentration of a salt solution affects the focal length of the hollow lens.

The following apparatus is available to the student:

illuminated object
hollow glass lens on a stand
several containers of salt solution with different known concentrations (e.g., $0%0\%$ , $5%5\%$ , $10%10\%$ , $15%15\%$ , $20%20\%$ )
screen
metre ruler
syringe or beaker (to fill and empty the lens)

Other laboratory apparatus normally available in a school laboratory can also be used.

In your plan, you should:

draw a labelled diagram to show the arrangement of the apparatus
explain briefly how you would carry out the investigation, including the measurements you would take
draw a suitable table, with column headings and units, to show how you would display your readings (you are not required to enter any data)
state how you would use your results to reach a conclusion.

[8]

A student investigates how the concentration of a salt solution inside a hollow, double-convex lens affects its focal length.

The focal length $f$ of the lens is given by the equation:

\frac{uv}{u+v}

where $u$ is the distance between the illuminated object and the lens, and $v$ is the distance between the lens and the sharp image formed on a screen.

Plan an experiment to investigate how the concentration of a salt solution affects the focal length of the hollow lens.

The following apparatus is available to the student:

illuminated object
hollow glass lens on a stand
several containers of salt solution with different known concentrations (e.g., $0%0\%$ , $5%5\%$ , $10%10\%$ , $15%15\%$ , $20%20\%$ )
screen
metre ruler
syringe or beaker (to fill and empty the lens)

Other laboratory apparatus normally available in a school laboratory can also be used.

In your plan, you should:

draw a labelled diagram to show the arrangement of the apparatus
explain briefly how you would carry out the investigation, including the measurements you would take
draw a suitable table, with column headings and units, to show how you would display your readings (you are not required to enter any data)
state how you would use your results to reach a conclusion.

3.2.3a Converging and diverging lenses

Question 11

Markscheme

3.2.3a Converging and diverging lenses

Question 11

Markscheme

3.2.3a Converging and diverging lenses

Question 11

3.2.3a Converging and diverging lenses Questions

3.2.3a Converging and diverging lenses

Question 11

3.2.3a Converging and diverging lenses Questions