An electron entering thomson’s e/m apparatus has an initial velocity (in horizontal direction only) of 4.0 x 10 6 m/s. in the lab there is a permanent horseshoe magnet of strength 12 mt, which you would like to use. (a) what electric field will you need in order to produce zero deflection of the electrons as they travel through the apparatus? (b) the length of nonzero e and b fields is 2.0 cm. when the magnetic field is turned off, but the same electric field remains, how far in the vertical direction will the electron beam be deflected over this length?

Two loudspeakers, 5.5 m apart and facing each other, play identical sounds of the same frequency. you stand halfway between them, where there is a maximum of sound intensity. moving from this point toward one of the speakers, you encounter a minimum of sound intensity when you have moved 0.33 m . assume the speed of sound is 340 m/s.part a) what is the frequency of the sound? part b) if the frequency is then increased while you remain 0.21 m from the center, what is the first frequency for which that location will be a maximum of sound intensity? express your answer to two significant figures and include the appropriate units.