Answer:
Fuel cells have a higher efficiency than diesel or gas engines.
Most fuel cells operate silently, compared to internal combustion engines.
Fuel cells can eliminate pollution caused by burning fossil fuels.
First change km/ s into m/s, then use the formula
Lambda = velocity/ frequency
Answer:

Explanation:
Rydberg formula is used to calculate the wavelengths of the spectral lines of many chemical elements. For the hydrogen, is defined as:

Where
is the Rydberg constant for hydrogen and
,
are the lower energy state and the higher energy state, respectively.
