For each of the four statements below, indicate whether the statement is true or false, and provide your reasoning by identifying and applying concepts. (For each, 1/2 mark one or

more relevant physics for correctly selecting true or false, plus 2 marks for your reasoning.) As a sound wave moves from air into a solid medium, its frequency will change.а. b. If you are stationary while a car approaching you sounds its horn, you will hear the horn's frequency increase C. When a solid object becomes positively charged, it must have received additional protons relative to the number that the object had previously. d. In a correctly functioning electrical device, the ground or earthing wire should carry no current.