Question 14

(a) Explain the terms:

(i) transmutation as it relates to radioactivity; (ii) stopping potential.

(b) \(^{23}_{11}A + ^2_1B\) —> \(^p_qC\) + proton

\(^p_qC\) —> \(^r_sE\) + beta


A nucleus C, formed artificially from A and B radioactive and quickly decays to another nucli E as indicated in the nuclear equations abc Datermine the values of p, q, r and s.

(c) A certain metal of work function 1.6 eV is irradiated with ultra-violet light of wavelength 3.6 x 10\(^{-7}\) Calculate the maximum

(i) kinetic energy of ejected electron in joules;

(ii) speed of an emitted electron. (1eV = 1.6 x 10\(^{-18}\) J; C = 3.0 x 10\(^{8}\) ms\(^{-1}\); m, = 9.1 x 10\(^{-31}\) kg; h = 6.6 x 10\(^{-34}\) Js)

(d) If source of the ultra-violet light in (c) above is mo away from the surface of the metal, state the of on the maximum speed of the ejected electron

Theory

Question details

Exam body
WAEC
Subject
Physics
Year
2011
Question no.
#14
Type
Theory

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