The critical wavelength for producing photoelectric effect in a metal is `2500 Å` What wavelength would be nuccesary be produce photoelectric effect from this metal , having twice the KE of these produced at `2000 Å`

Explanation

To solve the problem, we need to find the wavelength necessary to produce the photoelectric effect in a metal, given that the critical wavelength is 2500 Å and that this new wavelength produces photoelectrons with twice the kinetic energy of those produced at a wavelength of 2000 Å.

### Step-by-Step Solution:

1. **Understanding the Critical Wavelength**:
- The critical wavelength (λ₀) is given as 2500 Å. This is the wavelength at which the kinetic energy (KE) of the emitted photoelectrons is zero.
- At this wavelength, the energy of the incoming photons is just enough to overcome the work function (Φ) of the metal.

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