When a certain metal was irradiated with light of frequency `4.0 xx 10^(19)s^(-1)` the photoelectrons emitted had three times the kinetic energy as the kinetic energy of photoelectrons emitted when the metal was irradited with light of frequency `2.0 xx 10^(16) s^(-1)` .Calculate the critical frequency `(v_(0))` of the metal

Explanation

To solve the problem, we will use the photoelectric effect equation derived from Einstein's photoelectric equation. The steps are as follows:

### Step 1: Write down the photoelectric equation
The kinetic energy (KE) of the emitted photoelectrons can be expressed using Einstein's photoelectric equation:
\[ KE = h \nu - h \nu_0 \]
where:
- \( KE \) is the kinetic energy of the emitted photoelectrons,
- \( h \) is Planck's constant,
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