The mass of photon of wavelength `lambda` is given by

Options

A. `hlambdac`
B. `h//lambdac`
C. `hc//lambda`
D. `hlambda//c`

Answer

To find the mass of a photon in terms of its wavelength \( \lambda \), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the relationship between wavelength and momentum**:
The de Broglie wavelength \( \lambda \) is given by the formula:
\[ \lambda = \frac{h}{p} \]
where \( h \) is Planck's constant and \( p \) is the momentum of the photon.

2. **Express momentum in terms of mass and velocity**:
For a photon, the momentum \( p \) can also be expressed as:
\[ p = mv \]
where \( m \) is the mass and \( v \) is the velocity. Since a photon travels at the speed of light \( c \), we can write:
\[ p = mc \]

3. **Substitute the expression for momentum into the wavelength formula**:
By substituting \( p = mc \) into the de Broglie wavelength equation, we have:
\[ \lambda = \frac{h}{mc} \]

4. **Rearranging the equation to solve for mass**:
To find the mass \( m \) of the photon, we can rearrange the equation:
\[ mc = \frac{h}{\lambda} \]
Dividing both sides by \( c \) gives:
\[ m = \frac{h}{\lambda c} \]

5. **Final expression for the mass of the photon**:
Thus, the mass of the photon in terms of its wavelength \( \lambda \) is:
\[ m = \frac{h}{\lambda c} \]

### Conclusion:
The mass of a photon of wavelength \( \lambda \) is given by:
\[ m = \frac{h}{\lambda c} \]