Which of the following statements is NOT true? 1)The average magnitude of the Poynting vector is the intensity of a wave 2)Momentum per unit time per unit area carried by an EM wave is called radiation pressure 3)The speed of light in a vacuum is constant 4)EM waves with very large wavelengths are called gamma rays

Farmer a has a deep well and needs a lot of water for her animals and crops. her neighbor, farmer b, has a shallower well. he needs less water than farmer a because his farm is smaller. in years of drought, sometimes farmer b can't get any water from his wells. what can farmer b do to decrease the likelihood of his well running dry?