A photon of wavelength 2.0 nm Compton-scatters from an electron at an angle of 90°. What is the modified wavelength? (    )

The wavelength of this musical note(音符) is 7.8 ft, over three times longer than the wavelength of the same note in air (2.5 ft).

The wrong statement about the formula is ( ) A: The higher the frequency, the shorter the wavelength B: The lower the frequency, the shorter the wavelength C: The worse the penetration, the higher the discrimination D: the better the penetration, the lower the discrimination

What is the shortest wavelength present in the Brackett series of spectral lines? (  )

The wavelength ____ which the eye is most sensitive is 5.5×10-5 cm.

Nonselective scattering is caused by particles that are much larger than the wavelength of the scattered radiation. （ ）

中国大学MOOC: The wavelength range of UV-B is .(280 nm-320 nm / 320 nm-360 nm)

The momentum of photons corresponding to the minimum wavelength emitted from x-ray tube whose operating voltage is 120 kV is (  )

The wavelength range of UV-A is ( ). A: 400 nm-600 nm B: 400nm-700nm C: 200nm-400nm D: 320 nm-400 nm

Plants can detect what about light? A: Direction B: Intensity C: Wavelength D: All of the above