. Elements of radio telephony . quency than theblue, while having no visible effect on the eye, will affect aphotographic plate and produce other manifestations. Aswe go stiU higher we come upon the very short waves of highpenetrative power known as X-rays. These rays are invis-ible to the eye but are capable of affecting photographicplates and also produce luminous effects when impingingupon certain chemicals. Radio and light waves are identical except for the differ-,ence in frequency; it so happens that the human eye is sensi- EIGH-FBEQUENCY CURRENTS 9 tive to a rather restricted band of fr

- Image ID: 2CRMY98

. Elements of radio telephony . quency than theblue, while having no visible effect on the eye, will affect aphotographic plate and produce other manifestations. Aswe go stiU higher we come upon the very short waves of highpenetrative power known as X-rays. These rays are invis-ible to the eye but are capable of affecting photographicplates and also produce luminous effects when impingingupon certain chemicals. Radio and light waves are identical except for the differ-,ence in frequency; it so happens that the human eye is sensi- EIGH-FBEQUENCY CURRENTS 9 tive to a rather restricted band of fr

Reading Room 2020 / Alamy Stock Photo

Image ID: 2CRMY98

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