The teacher is demonstrating the experiment of the focal length of a convex lens using the u-v…
Physics20251 markNumerical
The teacher is demonstrating the experiment of the focal length of a convex lens using the u-v method. After the teacher takes readings P and Q, he/she assigns two students (Student 1 and Student 2) to take the subsequent readings, assuming that the teacher is right. The graph shows the readings.
What is the focal length of the given lens?
Figure 75
Answer
Answer
Official answer key
Focal length by using the teacher's reading
$\frac{1}{f} = \frac{1}{20} + \frac{1}{20} = \frac{2}{20} = \frac{1}{10}$
$\Rightarrow f = 10$ cm
