Question

a microscope with converging lens (eyepiece) has a focal lenght of f1= 1.42cm mounted on one end of a tube of adjustable lenght. the other end is another converging lens (the objective)that has a focal lenght of f2=14.65 cm. when you place the flea at a distance of s1=3.20cm from the objective, find the overall lenght (cm) of the microscope needed to view the sample (a flea) in focus with a relaxed eye.

hint(a normal relaxed eye will expect to find the image at infinity. the L of the microscope here is the distance between the eyepiece and the objective lens shown in the figure)

sexepiece lens fr l microscope length I objective lens or co MY Express your answer in cm and to two decimal places

Answer 1

for final image at infinity first lens must be image of at focus of and lens. 1st lens. (6= -3.20cm f = 1042cm %= ? 1 1 V "If V = uf -3-20 X 1062 utf = 2.55cm -3.20 +1.42 length of telescope | Vot fel = 2.55 t 14.65 = 17.2cm Answer.