Which of the following statements is incorrect ?

Options

A. To increase the magnetic strength, increase the number of strokes while creating magnets.
B. To increase the magnetic strength, increase the number of coils around the nail.
C. Magnetic force is a pulling force only.
D. Magnet may lose its magnetic property when heated to a very high temperature.

Explanation

To determine which statement is incorrect, let's analyze each statement one by one:

1. **To increase the magnetic strength, increase the number of strokes while creating magnets.**
- This statement is **correct**. Increasing the number of strokes while rubbing a magnet against a magnetic material enhances the magnetization of that material.

2. **To increase the magnetic strength, increase the number of coils around the nail.**
- This statement is also **correct**. When creating an electromagnet, increasing the number of coils of wire around a nail increases the magnetic field strength.

3. **Magnetic force is a pulling force only.**
- This statement is **incorrect**. Magnetic force can be both attractive and repulsive. For example, like poles repel each other (north-north or south-south), while opposite poles attract (north-south).

4. **Magnet may lose its magnetic property when heated.**
- This statement is **correct**. Heating a magnet can cause it to lose its magnetic properties, especially if the temperature exceeds a certain threshold known as the Curie temperature.

Based on the analysis above, the incorrect statement is: **Magnetic force is a pulling force only.**