Answer:
434 Hz
Explanation:
According to the Doppler effect, when a source of a wave is moving towards an observer at rest, then the observer will observe an apparent frequency which is higher than the original frequency of the source.
In this situation, Tina is driving towards Rita. Tina is the source of the sound wave (the horn), while RIta is the observer. Since the original frequency of the sound is 400 Hz, Rita will hear a sound with a frequency higher than this value.
The only choice which is higher than 400 Hz is 434 Hz, so this is the frequency that Rita will hear.
Answer:
641 nm.
Explanation:
Given that,
A transmission grating has 5200 slits/cm.
We need to find the longest wavelength that can be observed in the third order. Using grating equation as follows :
...(1)
d is slit spacing
No fo slit per unit length :

We know that, N = 1/d
For longest wavelength, θ = 90°
From equation (1)

Hence, the longest wavelength in third order for a transmission grating is 641 nm.
Answer:
Because sound doesn't move in vacuum (of space)