Problem 5. Shown below are the essentials of a commercial mass spectrometer. This device is used to measure the composition of gas of samples, by measuring the abundance of the species of different masses. An ion of mass m and charge = 4 is produced in source S, a chamber in which a gas is taking place. The initially stationary ion leaves S, is accelerated by a potential difference AV > 0, and then enters a selector chamber, 5}, in which there is an adjustable magnetic field By, pointing out of the page and a deflecting electric field E, pointing from positive to negative plate. Only particles of a uniform velocity v leave the selector. The emerging particles at S5 enter a second magnetic field B., also pointing out of the page. The particle then moves in a semicircle, striking an electronic sensor at a distance x from the entry slit. Express your answers to the questions below in terms of E= |f}|, e, r, m, By = ]]2|, Av, and i, J, k if necessary. electronic sensor | Problem 5 (a) What magnetic field B, in the selector chamber is needed to ensure that the particle is straight through? (b) Find an expression for the mass of the particle after it has hit the electronic sensor at a distance r from the entry slit