Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

12 Cards in this Set

  • Front
  • Back
  • 3rd side (hint)

Wilhelm Conrad Roentgen

Physicist who discovered the x-ray.

Heinrich Geissler

Built the first vacuum tube.

Johann Wilhelm Hittorf

German physicist who used the vacuum tube to study fluorescence.

William Crookes

An English chemist that redesigned the vacuum tube. Discovered that cathode rats were streams of charged particles.

Protons +

Philip Lenard

Discovered that cathode rays could penetrate a thin window of aluminum foil in the walls of the glass tubes that cause fluorescent screens to glow. When aluminum was made thicker, the fluorescent screens would not glow.


Otto Walkhoff

German dentist who made first radiograph.

Pioneer. Dentist.

W.J. Morton

New York physician who made the first dental radiograph in the U.S. using a skull. Lectured on the usefulness of radiographs. Made the first full body radiograph.


C. Edmund Kells

New Orleans dentist who is credited with the first practical use of radiographs in dentistry. Exposed the first dental radiograph in the U.S. on a living person.

Got cancer in his hands from overexposure.

William H. Rollins

Developed the first dental x-ray unit.

Burned hand from overexposure.


Frank Van Woert

First to use film in intramural radiography.


Howard Riley

Established the first college course in radiography for dental students.


William D. Coolidge

Developed the first hot cathode X-ray tube, a high-vacuum tube that contained a tungsten filament.