Alexandra knows that the atomic number of the element potassium, k, is 19. she also knows that one particular isotope of potassium has a mass number of 39. how many neutrons can be found in the nucleus of this isotope of potassium?

a) 19

b) 20

c) 39

d) 58

Starting with only the balmer series light (visible light), how could we ensure that the solar panels generate a current that mark can use for his power station? a)by gradually increasing the brightness (amount) of light that we shine on it. b)by gradually increasing the frequency of the light we shine on it. c)by gradually increasing the wavelength of the light that we shine on it.

If a substance is in the gas phase, which of qualities of the gas will stay constant? a: volume b: mass c: shape d: position of particles

While you are driving in the lane next to the curb on a multi-lane road the car on your left suddenly moves toward you lane. they are about toy crash into your front fender. you