It is not possible to see very small objects, such as viruses, using an ordinary light microscope. An electron microscope, however, can view such objects using an electron beam instead of a light beam. Electron microscopy has proved invaluable for investigations of viruses, cell membranes, and subcellular structures, bacterial surfaces, visual receptors, chloroplasts, and the contractile properties of muscles. The βlensesβ of an electron microscope consist of electric and magnetic fields that control the electron beam. As an example of the manipulation of an electron beam, consider an electron traveling away from the origin along the x-axisΒ in theΒ XY plane with an initial velocity .Β Β As it passes through the regionΒ xΒ = 0 toΒ xΒ =Β d, the electron experiences acceleration Β whereΒ axΒ andΒ ayΒ are constants. For the caseΒ viΒ = 1.80 Γ 107Β m/s,Β axΒ = 8.00 Γ 1014Β m/s2, andΒ ayΒ = 1.60 Γ 1015Β m/s2Β determine atΒ xΒ =Β dΒ = 0.010 0 m (a) the position of the electron, (b) the velocity of the electron, (c) the speed of the electron, and (d) the direction of travel of the electron (i.e., the angle between its velocity and the x-axis).