Which statement is true? a. a resistor alters current and a switch turns current on and off b. a resistor measures voltage, and a switch changes ac to dc or dc to ac c. a resistor alters current and a switch measures voltage d. a resistor changes ac to dc or dc to ac, and a switch turns current on and off

On his honeymoon, james joule attempted to explore the relationships between various forms of energy by measuring the rise of temperature of water which had fallen down a waterfall on mount blanc. what maximum temperature rise would one expect for a waterfall with a vertical drop of 20 m? the specific heat of water is 4186 j/kg ∙ k. a)0.064 c° b)0.053 c° c)0.071 c° d)0.047 c°