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13. A wave has wavelength equal to 0.75 m and frequency 440 Hz. What is the wave speed? 14. An electric stove draws 30.0 amps at 220 Volts. What power does this stove consume? 15. A motorcycle drives past you. As it approaches you the frequency of its sound and as it goes away from you its frequency a) is normal, is normal b) gets lower, gets higher c) gets louder, gets quieter d) gets higher, gets lower e) gets softer, gets louder 16. An AC unit draws 30 amps of current while operating at 240 V. What is its resistance? 17. The range of visible light for human beings is approximately: a) 400 m to 700 m b) 4 mm to 7 mm c) 400 mm to 700 mm d) 400 nm to 700 nm 18. A machine performs 33800 J of work while absorbing 92400 J of heat. Calculate the machine's efficiency. 19. 18000 J of work is done on a system during which 18000 J of heat is removed from that system. What is the change in the system's internal energy? 20. The real force of nature that holds together the nucleus of atoms is... a) The electromagnetic force b) Gravity c) The weak nuclear force d) The centripetal force e) The strong nuclear force