A student performs an experiment to determine the focal length $f$ of a thin converging lens. They measure various object distances $u$ and the corresponding image distances $v$ , and plot a graph of $cmv\text{ / cm}$ on the $y$ -axis against $cmu\text{ / cm}$ on the $x$ -axis.

The student draws a straight line on the graph connecting the coordinates $25.0)\text{ cm}$ and $45.0)\text{ cm}$ . State the equation of this line.

The straight line intersects the experimental curved graph at the point where $cmu_1 = 34.8\text{ cm}$ and $cmv_1 = 34.8\text{ cm}$ . Calculate the focal length $f$ of the lens using the equation:

\frac{u_1 + v_1}{4}

By substituting $u = v$ into the thin lens formula:

\frac{1}{f} = \frac{1}{u} + \frac{1}{v}

show that the equation $\frac{u_1 + v_1}{4}$ is mathematically correct for the intersection point where $u_1 = v_1$ .

The student draws a straight line on the graph connecting the coordinates $25.0)\text{ cm}$ and $45.0)\text{ cm}$ . State the equation of this line.

The straight line intersects the experimental curved graph at the point where $cmu_1 = 34.8\text{ cm}$ and $cmv_1 = 34.8\text{ cm}$ . Calculate the focal length $f$ of the lens using the equation:

\frac{u_1 + v_1}{4}

By substituting $u = v$ into the thin lens formula:

\frac{1}{f} = \frac{1}{u} + \frac{1}{v}

show that the equation $\frac{u_1 + v_1}{4}$ is mathematically correct for the intersection point where $u_1 = v_1$ .

3.2.3a Converging and diverging lenses

Question 15

Markscheme

3.2.3a Converging and diverging lenses

Question 15

Markscheme

3.2.3a Converging and diverging lenses

Question 15

3.2.3a Converging and diverging lenses Questions

3.2.3a Converging and diverging lenses

Question 15

3.2.3a Converging and diverging lenses Questions