Answer:
Correct answer: Wave's frequency f = 7.5 · 10¹⁴ Hz
Step-by-step explanation:
Given: wavelength λ = 4.0 · 10⁻⁷ m and
ultraviolet wave's speed V = 3 · 10⁸ m/s
The formula for calculating frequency is:
f = V / λ = 3 · 10⁸ / 4.0 · 10⁻⁷ = 0.75 · 10¹⁵ = 7.5 · 10¹⁴ Hz
f = 7.5 · 10¹⁴ Hz
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