Explanation:
When the length of the journal is equal to the diameter of the journal, the bearing is said to be a square bearing. This means that the length of the bearing is equal to the diameter of the bearing.

Types of Bearings:
There are different types of bearings used in mechanical engineering, including short bearings, long bearings, medium bearings, and square bearings. Each type of bearing has its own characteristics and applications.

1. Short Bearings:
Short bearings have a length that is less than the diameter of the bearing. These bearings are typically used in applications where space is limited or where a compact design is required.

2. Long Bearings:
Long bearings have a length that is greater than the diameter of the bearing. These bearings are used in applications where there is a need for increased load-carrying capacity or where the bearing needs to support a longer shaft.

3. Medium Bearings:
Medium bearings have a length that is between the diameter and the length of the bearing. These bearings are used in a wide range of applications and provide a balance between load-carrying capacity and space requirements.

4. Square Bearings:
Square bearings have a length that is equal to the diameter of the bearing. These bearings are used in applications where a compact design is required and where the load-carrying capacity is not the primary concern.

Advantages of Square Bearings:
- Compact design: Square bearings have a compact design due to their equal length and diameter, making them suitable for applications with limited space.
- Ease of installation: The equal length and diameter of square bearings make them easier to install compared to other types of bearings.
- Cost-effective: Square bearings are often more cost-effective compared to long bearings or other types of specialized bearings.
- Versatility: Square bearings can be used in a variety of applications and can accommodate different shaft sizes.

In conclusion, when the length of the journal is equal to the diameter of the journal, the bearing is referred to as a square bearing. Square bearings have a compact design, are easy to install, cost-effective, and versatile in their applications.