A photon will have less energy if its

Options

A. amplitude is higher
B. frequency is higher
C. wavelength is longer
D. wavelength is shorter

Answer

To solve the question, we need to understand the relationship between the energy of a photon, its frequency, and its wavelength.

### Step-by-Step Solution:

1. **Understanding Photon Energy**:
The energy (E) of a photon is given by the formula:
\[ E = h \cdot f \]
where \( h \) is Planck's constant and \( f \) is the frequency of the photon.

2. **Relationship Between Frequency and Wavelength**:
The frequency (f) of a photon is related to its wavelength (λ) by the equation:
\[ f = \frac{c}{\lambda} \]
where \( c \) is the speed of light.

3. **Substituting Frequency in Energy Equation**:
By substituting the expression for frequency into the energy equation, we get:
\[ E = h \cdot \frac{c}{\lambda} \]
This shows that energy is inversely proportional to wavelength.

4. **Analyzing the Relationship**:
From the equation \( E = \frac{h \cdot c}{\lambda} \), we can see that:
- If the wavelength (λ) increases, the energy (E) decreases.
- Conversely, if the wavelength decreases, the energy increases.

5. **Conclusion**:
Therefore, a photon will have less energy if its wavelength is longer.

### Final Answer:
A photon will have less energy if its **wavelength is longer**.