Answer:
6.25 ×10^10 Hz
Step-by-step explanation:
If the distance between five successive crests is 2.4 cm, then the distance between each crest is 2.4/5 = 0.48 cm or 0.0048 m or 4.8 ×10^-3 m
Since the velocity of a wave is given by;
v= λf
Where;
λ= wavelength of the wave
f= frequency of the wave
But λ= distance between successive crests = 4.8 ×10^-3 m
v= 3×10^8 ms-1 (speed of electromagnetic waves in vacuum)
f= v/λ
f= 3×10^8 ms-1/4.8 ×10^-3 m
f= 0.625 ×10^11 Hz
f= 6.25 ×10^10 Hz