What frequency (in Hz) is received by a person watching an oncoming ambulance moving at 120 km/h and emitting a steady 800 Hz sound from its siren? The speed of sound on this day is 345 m/s.

In a laboratory, nakisha mixes sodium hydroxide solution with an indicator called phenolphthalein. when combined, they create a pink solution. nakisha wonders if mixing other solutions with phenolphthalein will also create this pink color. how could she use the scientific inquiry process to explore it further?

What type of light does this light bulb produce most (i.e. at what wavelength does the spectrum have maximum intensity)?

It is really hard for me right know