Photoelectric Effect Flashcards

1
Q

What was first used to describe/show it?

A

Cathode ray tube: the cathode became positively charged when UV light was incident upon it

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2
Q

Results of the photoelectric effect
1) no ___ were emmited until what?
Difference between quantum theory and wave theory

A

1) electrons—no matter how intense the EMR was until a certain minimum frequency was reached

Intensity/amplitude does not cause photo emission but wave theory says it should. Quantum says E is directly proportional to frequency and it causes photoemission

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3
Q

Photoelectric effect

2) is f is is smaller than do what happens?

A

No electrons are emitted no matter how intense the EMR is

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4
Q

3) is f is bigger than fo what happens?

A

Electrons are emitted instantly, no delay at all

-wave energy takes some time to be absorbed

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5
Q

4) each material used as a cathode has its own ___?

A

Threshold frequency

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6
Q

5) is f is bigger than fo AND the emr is intensified what happens?

A

More electrons are emitted
-with quantum theory more photos means more e-‘s, and since each electron can absorb a single photon this means photoelectric current increases
(Wave theory says bigger intensity, bigger electron energy but it doesn’t)

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7
Q

Scientist responsible?

A

Heinrich Hertz

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8
Q

6) is f is bigger than fo AND f is increased what happens?

A

The emitted electrons have more energy (faster)

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9
Q

Conservation of energy equation for the photoelectric effect

A

Ephoton=Eke- + W

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10
Q

Variations of the conservation of energy equation

A

Hf=1/2mv^2 +hfo

Hc/wavelength= qVstop + hc/threshold wavelength

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