The brightnes producing capacity of a source

Options

A. does not depend on its power
B. does not depend on the wavelength emitted
C. depends on its power
D. depends on the wavelength emitted

Answer

To solve the question regarding the brightness producing capacity of a source, we need to analyze the factors that influence brightness.

### Step-by-Step Solution:

1. **Understanding Brightness**: Brightness is a measure of how much light is emitted from a source and how it is perceived by the human eye. It is often quantified in terms of luminous flux, which is the total amount of visible light emitted by a source.

2. **Luminous Flux**: The total luminous flux (\( \Phi \)) produced by a light source can be expressed as:
\[ \Phi = \eta \times P \]
where \( \eta \) is the luminous efficacy (a measure of how well a light source produces visible light) and \( P \) is the total power consumed by the source.

3. **Dependence on Power**: From the equation above, we can see that luminous flux (and thus brightness) directly depends on the total power (\( P \)). Higher power means more energy is available to produce light, leading to greater brightness.

4. **Dependence on Wavelength**: The brightness also depends on the wavelength of the emitted light. Human eyes are more sensitive to certain wavelengths (around 555 nm, which corresponds to green light). Therefore, if a source emits light in the range of 400 to 700 nm, the relative luminosity is higher, which means that the perceived brightness will be greater for those wavelengths.

5. **Conclusion**: Based on the analysis, the brightness producing capacity of a source depends on both its power and the wavelength of the emitted light. Therefore, the correct options are:
- It depends on power.
- It depends on the wavelength emitted.

### Final Answer:
The brightness producing capacity of a source depends on:
- Power
- Wavelength emitted