The Chemistry Book

Lesson: 49
Unit: 1
State Content Standard: 1h

Lesson Title: Photoelectric Effect
Textbook page: Not in Textbook
Chemistry Passport: Page 63

Objectives
1. Know what the photoelectric effect is.
2.Know which elements are affected by the photoelectric effect.
3.Know how the color of the light is important in the photoelectric effect.

Lesson Content

Photoelectric Effect

       -metals give off electrons, called photoelectrons, when light is shone on them

       -only certain frequencies of light will cause the release of photoelectrons

       -different frequencies of light have more/less energy than other frequencies

Einstein and the Photoelectric effect

       -saw that metal gave off electrons when certain colors of light were shone on it

       -discovered that is not a wave; it is made of little bundles of energy

       -he called those bundles of energy photons

       -photons knock electrons out of orbit when they collide

1. Which elements are affected by the photoelectric effect?

A) Gases

B) Nonmetals

C) Metals

D) Semimetals

Correct answer: Metals. Metals give off electrons when light is shone on them.

2. What are released?

A) Neutrons

B) Protons

C) Gamma rays

D) Electrons.

Correct answer: Electrons. When light is shone on them, metals give off electrons.

3. Why is the frequency of the light important?

A) Different frequencies of light have different amounts of energy.

B) The frequency does not matter.

C) Only one frequency of light causes all metals to give off photoelectrons.

D) Different frequencies of light cause different particles to be released from the metal.

Correct answer: Different frequencies of light have different amounts of energy. Different frequencies of light have more/less energy than other frequencies.

4. Why was Einstein’s experiment important?

A) He found that light was a wave.

B) He discovered the photon.

C) His experiment wasn’t important.

D) He discovered the electron.

Correct answer: He discovered the photon. Einstein found that light was made of little bundles of energy called photons.

5. What knocks the electrons out of orbit, creating photoelectrons?

A) Gamma rays

B) Protons

C) Atoms

D) Photons

Correct answer: Photons. Light is made of small bundles of energy called photons which collide with electrons, knocking them out of orbit.

Further Reading

http://www.einsteinyear.org/facts/photoelectric_effect/

References