Exam II Sp2016-Science 25

_____14. Which of the following substances is most likely to have the largest “energy gap”? a) aluminum b) copper c) rubber d) mercury e) a semiconductor _____15. Solar calculators function by using specially-made a) conductors b) semiconductors c) superconductors d) insulators e) resistors _____16. When an object is placed at the focal point of a converging lens, the image is formed at a) the focal point b) zero c) the surface of the lens d) at infinity e) converging lenses never have real images _____17. A diverging lens a) never has an image formed b) is called a positive lens c) is called a negative lens d) has only real images e) has no focal point _____18. As the object distance from a converging lens is doubled, the focal length of the lens a) also doubles b) halves c) quadruples d) decreases by 4x e) remains the same _____19. When s siren approaches an observer, the pitch is higher due to a) the Doppler effect b) the Ramsaur effect c) an increased amplitude d) a decreased amplitude e) an increased speed of the wave _____20. As the wavelength of EM radiation increases, its energy a) increases b) decreases c) remains the same d) changes in proportion to its amplitude e) changes in proportion to its increased speed

_____37. Another name for an energetic gamma ray is a) electron b) photon c) positron d) alpha e) beta _____38 . The half -life of element X is 2 days. How much X remains from a 16 g sample after 8 days? a) 2 g b) 4 g c) 8 g d) 1 g e) 12 g _____39. After 2 days only 1/64 of a radioactive sample remains. What is the half-life of this sample? a) 2 hours b) 4 hours c) 6 hours d) 8 hours e) 12 hours _____40. Element X is radioactive and turns into element Y . The half-life of X is 8 days. What percentage of this sample has transformed into Y after 24 days? a) 12.25  b) 87.75  c) 22.55  d) 2.45  e) 68.18  _____41. Element Z with 86 protons, undergoes 8 gamma, four alpha, 10 positive beta and 12 negative beta decays. How many protons does the resulting nucleus have? a) 78 b) 72 c) 88 d) 80 e) 74 _____42. Element X with 34 protons, undergoes 2 gamma, eight alpha, 16 positive beta and 2 negative beta decays. How many protons does the resulting nucleus have? a) 42 b) 28 c) 16 d) 22 e) 4 _____43. Evidence that the Universe is indeed expanding is provided by a) Coulomb’s Law b) the Law of Claussius c) Bernoulli’s Principle d) the Law of entropy e) the redshift of the EM spectrum