The wires connecting the switches, light-bulbs and buzzers must start and end at the power source before the circuit can work. the power source could be a a) battery. b) light-bulb. c) switch. d) wire.

Identify the theory that can be used to explain each phenomenon. answers diffraction: wave theory interference: wave theory reflection: both particle and wave theories refraction: both particle and wave theories

Which of these has some mechanical energy? a. an atom b. heat inside earth c. a book on a shelf d. the fire from a lit match

Which sections of the heating curve illustrate this process?