The isotope iodine-131 emits two types of nuclear radiation. Gamma radiation is one of the types emitted. A sample of iodine-131 produces a narrow beam of radiation which passes into a magnetic field. Fig. 10.1 shows some of the paths taken in the magnetic field by the radiation emitted from the sample. [Figure 10.1]

1. (a)(i)The direction of the magnetic field is into the page. On Fig. 10.1, mark with a gamma symbol (γ) any of the paths taken by the gamma radiation.[1]
2. (a)(ii)Determine the other type of radiation emitted by iodine-131. Explain how you obtain your answer. type of radiation .......................... explanation ..........................[4]
3. (a)(iii)In another experiment, the beam of radiation from the sample is incident on a 5mm thick sheet of lead. State what happens to the two types of radiation in the beam.[2]
4. (b)The gamma radiation produced has a frequency of 8.8 × 10¹⁹ Hz. The speed of electromagnetic radiation in a vacuum is 3.0 x 10⁸m/s. Calculate the wavelength of this gamma radiation in a vacuum. wavelength = .......................... m[2]

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