It is easier to remove an electron from sodium then from copper. Which metal has higher value of threshold frequency?

Explanation

To determine which metal, sodium or copper, has a higher threshold frequency, we need to analyze the relationship between the ease of electron emission and the work function of each metal.

### Step-by-Step Solution:

1. **Understanding the Photoelectric Effect**: The photoelectric effect occurs when light (photons) hits a metal surface and causes the emission of electrons. The energy of the incoming photons must be greater than or equal to the work function (ϕ) of the metal for electrons to be emitted.

2. **Work Function and Threshold Frequency**: The work function (ϕ) of a metal is related to its threshold frequency (ν₀) by the equation:
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