Question about textbook answer

[VZX]

From the textbook: When an electron beam strikes a block of copper, x-rays with a frequency of 2.0*10^18 Hz are emitted. What is the wavelength (in picometers) of these x-rays?

By plugging the frequency into c=wavelength*frequency, I got the wavelength of 150 pm but the answer that the textbook gives is 150 nm. Is this a typo or have I done something wrong?

[Antonia Valencia 2H]

Hi! The answer 150 pm is indeed the correct answer, so I'm assuming the textbook's answer key that you're looking at is simply a typo! Also, the question itself asked for picometers, so you're definitely doing the right thing. Hope this helps.