Chapter 1, Problem 2DQ

A camera lens used for taking close-up photographs has a focal length of 21.5 mm. The farthest it can be placed from the film is 34.0 mm. (a) What is the closest object (in mm) that can be photographed? 58.5 mm (b) What is the magnification of this closest object? 0.581 × ×

Given two particles with Q = 4.40-µC charges as shown in the figure below and a particle with charge q = 1.40 ✕ 10−18 C at the origin. (Note: Assume a reference level of potential V = 0 at r = ∞.) Three positively charged particles lie along the x-axis of the x y coordinate plane.Charge q is at the origin.Charge Q is at (0.800 m, 0).Another charge Q is at (−0.800 m, 0).(a)What is the net force (in N) exerted by the two 4.40-µC charges on the charge q? (Enter the magnitude.) N(b)What is the electric field (in N/C) at the origin due to the two 4.40-µC particles? (Enter the magnitude.) N/C(c)What is the electrical potential (in kV) at the origin due to the two 4.40-µC particles? kV(d)What If? What would be the change in electric potential energy (in J) of the system if the charge q were moved a distance d = 0.400 m closer to either of the 4.40-µC particles?

(a) Where does an object need to be placed relative to a microscope in cm from the objective lens for its 0.500 cm focal length objective to produce a magnification of -25? (Give your answer to at least three decimal places.) 0.42 × cm (b) Where should the 5.00 cm focal length eyepiece be placed in cm behind the objective lens to produce a further fourfold (4.00) magnification? 15 × cm