Thomson observed that cathode beams can pass undeflected through crossed electric and magnetic fields. Which of the following quantities must then be common to the particles making up these beams? A. Mass B. Size C. Magnitude of charge D. Sign of charge E. Sign and magnitude of charge F. Velocity

more than, less

less than, more

answer: a. same unit

explanation:

you'd use the equation that establishes a relationship between  energy  and  wavelength, which looks like this

e=h⋅cλ, where

λ  - the wavelength of the photon; c  - the speed of light, usually given as  3⋅108m/s; h  -  planck's constant, equal to  6.626⋅10−34j s

plug the value you were given for the energy of the photon in the above equation to get the wavelength

e=h⋅cλ⇒λ=h⋅ce

λ=6.626⋅10−34js⋅3⋅108ms−1.257⋅10−24j=1.581⋅10−1m