The lens equation says that if an object is placed at
a distance p from a lens, and an image is formed at a distance q from the lens, then the focal length f satisfies the equation 1/ f = 1/p +1/q. Assume that p = 2.3 ± 0.2 cm and q = 3.1 ± 0.2 cm.
a. Estimate f, and find the uncertainty in the estimate.
b. Which would provide a greater reduction in the uncertainty in f: reducing the uncertainty in p to 0.1 cm or reducing the uncertainty in q to 0.1 cm?