Question
Please help me out with all these question.
PHYSICS -Examination 1l- Continued 13 During an experiment, a scientist discovers that a dim source of red light will not cause a metal surface to discharge electrons. From your knowledge of the photoelectric effect, which of the following light sources might cause the metal surface to discharge electrons? (Choose as many as apply.) (A) a dim source of any electromagnetic radiation with a frequency lower than that of red lighn (B) a bright source of red light (C) a dim source of blue light (D) a bright source of blue light Which of the following would you expect to have the largest wavelength associated with it? (A) a quick-moving bee (B) an electron orbiting a nucleus (C) a slowly lumbering elephant (D) the earth orbiting the sun The atoms of heavier elements are not much larger than the atoms of lighter elements because (A) adding protons to the nucleus increases the electrical attraction on the orbiting electrons, creating smaller orbits (B) adding protons to the nucleus increases the electrical repulsion on the orbiting electrons, foreing thenm out of the higher energy levels (C) heavier elements tend to have fewer energy levels than lighter elements (D) none of these; atoms of heavier elements are. irn fact, much larger than the atoms of lighter elements. 15. 16. which of the following statements are true? (Choose as many as apply.) The nucleus (A) makes up only a tiny part of the volume of an atom (B) makes up most of the volume of an atom (C) accounts for only a tiny amount of the mass of an atom (D) accounts for most of the mass of an atom. An alpha particle is a (A) helium atom (B) helium nucleus (C) hydrogen atom (D) hydrogen nucleus. Which of the following statements are true about radioactive elements? (Choose as many as apply.) (A) They never decay into elements with lower atomic numbers. (B) They never decay into elements with higher atomic numbers. 18,
Explanation / Answer
13) C, D intensity doesn't matter in ejection of electrons. Any light of higher frequency might cause ejection of electrons.
14)C
15)D , heavier elements's atoms are bigger in size.
16)A,D
17)B
18)B