Two metals A and B have work function 2 eV and 4 eV , respectively . Which metal has a lower threshold wavelength for photoelectric effect ?

Explanation

To determine which metal has a lower threshold wavelength for the photoelectric effect, we need to analyze the relationship between the work function and the threshold wavelength.

### Step-by-Step Solution:

1. **Understand the Work Function**: The work function (φ) is the minimum energy required to remove an electron from the surface of a metal. It is given in electron volts (eV). In this case, metal A has a work function of 2 eV, and metal B has a work function of 4 eV.

2. **Use the Formula for Threshold Wavelength**: The threshold wavelength (λ₀) can be calculated using the formula derived from Planck's equation:
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