Isoquant curves have a negative or downward slope. For a specific isoquant, the amount of labor is always inversely related to the amount of capital used. So if capital or labor is reduced, the other factor should be increased to maintain the same output. Isoquants cannot slope upward.
Isoquants do not meet with each other or cross each other; they do not intersect. Different isoquants are created for different outputs for the same production function. Also, each isoquant relates to a particular rate of output. So an intersection of isoquants would show that the same amounts of labor and capital with the same efficiency can produce two different outputs. Similarly, isoquants cannot be tangential to each other.
Isoquants are usually convex toward the origin. That means every isoquant becomes flatter farther down its curve. As a result, the curve never can be parallel to the X or the Y axis. The isoquant remains part of an oval. If you travel along the isoquant downward and to the right, the values of labor and capital adjust with each other to keep output constant. So successive increments of capital result in reduction of labor. This is called the law of diminishing returns. As a result, the isoquant is convex toward the origin.
Each isoquant represents a particular level of output. In other words, you can trace a separate isoquant for every unit of change in output. You also can trace a different isoquant for every output rate. Each isoquant connects the alternative combination of inputs that are technologically efficient to attain a specific output. Isoquants that are farther from the origin represent higher output rates.