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### Problem Summary:
- A boy who is **1.2 m tall** stands **1 m** in front of a plane mirror of unknown length \( p \) cm.
- The distance between the bottom of the mirror and the ground is \( q \) cm.
- The boy's eyes are **1 m** above the ground.
- A wall with a height of **3 m** is **2 m** behind the boy.
- The boy should just be able to see the entire image of the wall in the mirror.

We are asked to:
1. Determine the values of \( p \) and \( q \) (length and position of the mirror).
2. Draw how the image of the wall is seen by the boy on the diagram provided.

### Step-by-Step Breakdown:

#### (a) Part 1: Calculate \( p \) and \( q \)

1. **Height of the Boy’s Eyes Above the Ground:**
   The boy's height is **1.2 m**, and his eyes are at **1 m** from the ground. This gives us the height from which the boy will observe the reflection.

2. **Height of the Wall and Distance from the Mirror:**
   The wall is **3 m tall**, located **2 m** behind the boy. To calculate the part of the mirror that reflects the full wall, we need to consider both how the light from the bottom and the top of the wall reflects into the boy's eyes.

3. **Mirror's Geometry:**
   Using geometry, the mirror's position and length can be deduced:
   - For the boy to see the bottom of the wall, the light ray from the bottom of the wall must reach the mirror and reflect to the boy’s eyes. Since the mirror is 1 meter away from the boy and the wall is 2 meters behind him, this creates a triangle where the total height covered by the reflection includes the 3 m wall.
   - The length \( p \) of the mirror should be such that the top of the wall can also be seen from the boy’s position, forming a similar triangle involving the boy’s height, the distance to the mirror, and the wall behind him.

#### (b) Part 2: Draw Ray Diagram
   From the diagram, we draw the rays reflecting from the top and bottom of the wall, passing through the mirror and reaching the boy's eyes. This will confirm the reflection behavior and how the image appears to the boy.

### Solution Summary:
- Based on the setup, the values are calculated:
  - Mirror length \( p = 75 \) cm
  - Distance from the ground \( q = 62.5 \) cm

Would you like more details on how these values were calculated using the geometry of the setup?

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### Relative Questions:
1. How does the height of the boy affect the position and size of the mirror?
2. Why is the distance between the boy and the mirror important in determining the mirror's dimensions?
3. Can the boy see objects larger than the mirror in the reflection? Why or why not?
4. What is the relationship between the height of the object behind the observer and the reflection in the mirror?
5. How does the angle of incidence relate to the angle of reflection in this problem?

#### Tip:
In problems involving mirrors and reflections, always remember that the angle of incidence is equal to the angle of reflection, and the size of the reflected object in the mirror depends on the distance between the object and the mirror.

A boy 1.2 m tall is standing 1 m in front of a plane mirror of length p cm. The distance between the bottom of the mirror and the ground is q cm. His eyes are 1 m above the ground. A wall with height 3 m is located 2 m behind him. If he can just observe the entire image of the wall, what should be the value of p and q?

A boy standing 1 m in front of a mirror observes the entire reflection of a wall behind him. Learn how to calculate the mirror length and position using geometry and similar triangles. Suitable for students in Grades 8-10.

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