Hydrogen atoms absorb energy so that the electrons are excited to n=4. Calculate the wavelength, in
nm, of the photon emitted when the electron relaxes to n=2.
487nm
456nm
4.56 x 10nm
4.87 x 10-7nm

54 km / hours

step-by-step explanation:

we need to convert seconds to hours

60 seconds = 1 minutes

60 minutes = 1hour

15 m         60 second   60 minutes

  * *         = 54000 meters/ hour

second     1 minute             1 hour

now we need to convert meters to km

1000 m = 1 km

54000 m       1 km

*   = 54 km / hours

hour               1000m

that one look

step-by-step explanation:

the answer on ed. is:

c. "the graph of f(x) has exactly two x-intercepts."

hope i could someone! : )

y=-2x0 is most likey your asnwer