In a cathode-ray oscilloscope (c.r.o.), a beam of electrons is produced by a filament at one end of an evacuated glass tube. The electrons are then accelerated and strike a screen at the other end of the tube.

1. (a)Describe how the electrons are produced by the filament and how they are then accelerated. ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ...............................................................................................................................................[3][3]
2. (b)Explain why the glass tube is evacuated. ...............................................................................................................................................[1][1]
3. (c)The instruction booklet for a c.r.o. states that strong magnets must not be placed close to the c.r.o. Explain why a strong magnet close to the c.r.o. deflects the electron beam. ............................................................................................................................................... ...............................................................................................................................................[2][2]