Action and reaction
(i) act on two different objects
(ii) have equal magnitude
(iii) have opposite directions
(iv) have resultant zero

Options

A. (i), (ii)
B. (ii),(iii)
C. (iii), (iv)
D. All options are correct

Answer

To solve the question regarding action and reaction forces, we will evaluate each statement one by one based on Newton's Third Law of Motion.

### Step-by-Step Solution:

1. **Understanding Action and Reaction Forces**:
- According to Newton's Third Law of Motion, for every action, there is an equal and opposite reaction. This means that forces always occur in pairs.

2. **Evaluating Statement (i)**: "Act on two different objects".
- Action and reaction forces act on two different bodies. For example, if a person pushes against a wall, the force exerted by the person on the wall is the action, and the force exerted by the wall back on the person is the reaction.
- **Conclusion**: This statement is **correct**.

3. **Evaluating Statement (ii)**: "Have equal magnitude".
- The action and reaction forces are always equal in magnitude. If a person exerts a force of 10 N on the wall, the wall exerts an equal force of 10 N back on the person.
- **Conclusion**: This statement is **correct**.

4. **Evaluating Statement (iii)**: "Have opposite directions".
- The action and reaction forces are directed opposite to each other. In the above example, if the person pushes the wall to the right, the wall pushes back to the left.
- **Conclusion**: This statement is **correct**.

5. **Evaluating Statement (iv)**: "Have resultant zero".
- When considering the action and reaction forces together, they do not produce a net force on a single object because they act on different objects. However, if we consider the system of both objects, the net force on the system is zero since the forces cancel each other out.
- **Conclusion**: This statement is **correct**.

6. **Final Conclusion**:
- Since all four statements are correct, we can conclude that the answer to the question is that all options are true.