A cathode ray tube and an X-ray tube are practical applications of thermionic emission. In these tubes thermionic emission releases electrons, which are then accelerated into a beam.
An electron is a subatomic particle. Name another subatomic particle and give two of its properties.
The diagram shows a simple cathode ray tube. AB
C (9)
high voltage (i) Name the parts labelled A, B, C.
(ii) Give the function of any two of these labelled parts. (iii) How can the beam of electrons be deflected? (iv) What happens at C when the electrons hit it? (v) Why is a vacuum needed in a cathode ray tube?
In an X-ray tube, a beam of electrons is used to produce X-rays. Draw a sketch of an X-ray tube.
2010
10. The photoelectric effect can be regarded as the inverse of X-ray production. (i) What is meant by the photoelectric effect?
(ii) Describe an experiment to demonstrate the photoelectric effect. (iii) Give two applications of the photoelectric effect.
(6)
(12) (6)
(9) (9) (6) (6) (3)
(11) Give one safety precaution taken by a radiographer when using an X-ray machine. (3 )
