TE Enriched Sample (E)

Chapter Exercise 37 Chapter Exercise Take h = 6.63 × 10 −34 J s, e = 1.60 × 10 −19 C and c = 3 × 10 8 m s −1 . For other physical constants, see the Appendix. Multiple-choice Questions 1. Ametal surface is illuminated by yellow light of wavelength 570 nm but no photoelectrons are emitted. It can be concluded that (1) the yellow light is not intense enough to induce the emission of photoelectrons. (2) the work function of the metal is larger than 2.18 eV. (3) photoelectrons will be emitted if the surface is illuminated by blue light of wavelength 470 nm. A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only 2. Ultraviolet radiation of frequency f is directed onto the cathode of a photocell of work function z . If a photoelectron is able to reach the positive anode of the photocell, its KE when emitted must be A. = hf − φ . B. ≥ hf − φ . C. ≥ hf + φ . D. ≤ hf − φ . 3. Photoelectrons are emitted by a metal surface S when ultraviolet radiation from a source X falls on it. A glass plate is then placed between S and X . Which of the following will decrease? (1) The number of photons emitted from X (2) The number of photoelectrons emitted per second (3) The work function of the metal A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only 4. Photoelectrons are emitted when electromagnetic radiation of a certain wavelength is directed onto the cathode of a photocell. Which of the following graphs is correct? N = number of photoelectrons emitted per second I = radiation intensity I p = photoelectric current V s = stopping potential (1.1 & 1.2) B (1.2) D (1.1 & 1.2) B (1.2) A. B. I 0 I p N I 0 C. D. I 0 V s I 0 V s 5. A student has a few photocells having cathodes of different work functions. Radiation beams of the same intensity but different frequencies are directed onto the cathodes of the cells. photocell work function / eV P 2.8 Q 3.3 R 4.0 radiation frequency / 10 14 Hz X 9.0 Y 10.0 Z 11.0 Which combination of photocell and radiation will result in the smallest stopping potential? A. P and X B. P and Z C. Q and X D. R and Y 6. In a photocell experiment studying the photoelectric effect, the following data is obtained. wavelength of light / nm cathode material work function / eV photocurrent / 10 −12 A 320 aluminium 4.1 0 320 lithium 2.3 1.0 What is the stopping potential for the photoelectrons emitted from lithiumwhen shone with light of wavelength 320 nm? Given hc = 1243 eV nm. A. . V 320 1243 4 1 - c m B. . V 320 1243 2 3 - c m C. 4.1 V D. 2.3 V C (1.2) D (1.2) B DSE Level-up Companion For more chapter-end questions (mock DSE type), see Level-up Task 71B . Sample © United Prime Educational Publishing (HK) Limited, Pearson Education Asia Limited 2023 All rights reserved; no part of this publication may be reproduced, photocopied, recorded or otherwise, without the prior written permission of the Publishers.