A Photocathode Having a Work Function Of $2.8 \mathrm { eV }$

question 14

Multiple Choice

A photocathode having a work function of $2.8 \mathrm { eV }$ is illuminated with monochromatic electromagnetic radiation whose photon energy is $4.0 \mathrm { eV }$ . What is the threshold (cutoff) frequency for photoelectron production? $\left( 1 \mathrm { eV } = 1.60 \times 10 ^ { - 19 } \mathrm {~J} , h = 6.626 \times 10 ^ { - 34 } \mathrm {~J} \cdot \mathrm { s } \right)$

• A) \(8.6 \times 10 ^ { 14 } \mathrm {~Hz}\)
• B) \(2.9 \times 10 ^ { 14 } \mathrm {~Hz}\)
• C) \(6.8 \times 10 ^ { 14 } \mathrm {~Hz}\)
• D) \(9.7 \times 10 ^ { 14 } \mathrm {~Hz}\)
• E) \(7.7 \times 10 ^ { 14 } \mathrm {~Hz}\)

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Definitions:

Qualitative Forecasting

A method of prediction that uses non-numerical information, such as expert opinions or market trends, to forecast future events.

Moving Average

A statistical measure used to analyze data points by creating a series of averages of different subsets of the full data set.

Time Horizons

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Jury of Executive Opinion Model

The Jury of Executive Opinion Model is a forecasting method where a group of senior managers estimates future outcomes based on their experience and insights.