Answer:
(a) Approximately 968 Hz.
Explanation:
The observed frequency is less than 1003 Hz because of Doppler's Effect. When the source is moving away from an observer that doesn't move, the equation for the observed frequency would be:
,
where in the context of this problem,
- is the speed of sound in the air.
- is the speed at which the source moves away from the observer.
- is the frequency at the source.
Apply this equation to find :
.
Here's an alternative explanation.
The frequency of the siren at the source is . That corresponds to a period of .
In other words, at the source, a peak arrives about every .
The source is moving away from the observer at a speed of . In the between the first and the second peak, the source moved away from the observer. It would take an extra for the sound to cover that extra distance.
As a result, the period of the sound would appear to be to the observer.
That corresponds to an observed frequency of . (Same as the answer from the formula.)
Visible light or electromagnetic radiation within 400nm to 700nm is responsible for colour of the spectrum.
Explanation:
The electromagnetic spectrum contains radiations of varying wavelength. The radiations with the lowest energy are characterised by the longest wavelength.
Within this spectrum lies the visible light which enables us to see a different colour. The radiations within the range 400nm to 700nm are included in the visible spectrum.
While violet lies at the 400nm spectrum part red colour lies at 700nm part. As the wavelength of the radiation transverses between 400-700 nm, the colour of the object changes accordingly.
Answer:
the detection of the equivalence point, the point at which chemically equivalent amounts of the reactants have been mixed.