Photoelectrons emitted from a metal have

Options

A. different speeds starting from 0 to certain maximum.
B. same kinetic energy
C. same frequency
D. Both B & C

Explanation

To solve the question regarding photoelectrons emitted from a metal, we need to analyze the behavior of these electrons when exposed to light. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Photoelectric Effect
The photoelectric effect occurs when light of sufficient frequency strikes a metal surface, causing the emission of electrons. The energy of the incoming photons must be greater than the work function of the metal for electrons to be emitted.

**Hint:** Recall that the work function is the minimum energy required to remove an electron from the surface of the metal.

### Step 2: Energy of the Incident Photons
The energy of the incident photons can be calculated using the equation:
\[ E = h \nu \]
where \( E \) is the energy of the photon, \( h \) is Planck's constant, and \( \nu \) is the frequency of the light.

**Hint:** Remember that the frequency of the light must be above a certain threshold for photoemission to occur.

### Step 3: Kinetic Energy of Emitted Electrons
When a photon strikes an electron, if the energy of the photon is greater than the work function (\( \phi \)), the excess energy is converted into kinetic energy (\( KE \)) of the emitted electron:
\[ KE = h \nu - \phi \]

**Hint:** The kinetic energy of the emitted electrons depends on the frequency of the incident light and the work function of the metal.

### Step 4: Distribution of Kinetic Energies
Due to the different interactions and collisions that each electron experiences within the metal before being emitted, the kinetic energies of the emitted photoelectrons will vary. Some electrons may have very little kinetic energy (just above the work function) while others may have maximum kinetic energy depending on the energy of the incident photons.

**Hint:** Consider that each electron may have a different path and experience different collisions, leading to a range of kinetic energies.

### Step 5: Conclusion on Speeds and Energies
Since the kinetic energy of the emitted photoelectrons varies from 0 up to a maximum value, it follows that the speeds of these electrons will also vary. Therefore, the correct answer to the question is that photoelectrons emitted from a metal have different speeds ranging from 0 to a certain maximum value.

**Final Answer:** The correct option is that photoelectrons emitted from a metal have different speeds starting from 0 to a certain maximum value.