A green leaf placed in a dark room is illuminated by red light. The leaf will appear to be

Options

A. green
B. red
C. yellow
D. black

Answer

To solve the question of what color a green leaf will appear when illuminated by red light in a dark room, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Color of the Leaf**:
- A green leaf appears green because it reflects green light and absorbs other colors (like red, blue, etc.).

2. **Analyzing the Light Source**:
- In this scenario, the leaf is illuminated by red light only. This means that the only color of light available to be reflected is red.

3. **Reflection and Absorption**:
- Since the green leaf reflects green light, it does not reflect red light. Instead, it absorbs red light.

4. **Conclusion on Appearance**:
- Because the green leaf absorbs the red light and there is no green light available to be reflected, the leaf will not reflect any light back to our eyes. Therefore, it will appear black.

5. **Final Answer**:
- The leaf will appear black when illuminated by red light in a dark room.