2. What is the frequency of a 6.9 x 10^-13 m wave?

frequency =v/π= 3×10^8/6.9 ×10^-13=5×10^20

Explanation:) the relationship between the velocity and frequency of a wave is V=fπ ,where V=velocity of wave while the π or lander represents wavelength which was given in the question.f represents frequency of wave.velocity of waves differs,e.g sound waves has a velocity of 330m/s while electromagentic spectrum waves eg UV,infrared has a constant velocity called velocity of light =3×10^8.the question did not clarify the type of wave so I assumed it should be light. Which has a V= 3×10^8.so frequency was calculate d using velocity divided by wavelength (which. Was given).

the answer would be c

it is b that is the answer.