When two wires have current in same direction then force is

Options

A. Attractive
B. Repulsive
C. Both attractive and repulsive
D. Can't be determined

Answer

To determine the force between two parallel wires carrying current in the same direction, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Direction of Currents**:
- Let’s denote the two wires as Wire 1 and Wire 2. Assume both wires carry current in the same direction (upward).

2. **Determine the Magnetic Field Created by Wire 1**:
- According to the right-hand thumb rule, if you point your thumb in the direction of the current in Wire 1 (upward), your fingers will curl around the wire. At the location of Wire 2, the magnetic field due to Wire 1 will be directed inward towards Wire 1.

3. **Calculate the Force on Wire 2 Due to Wire 1**:
- The formula for the magnetic force on a current-carrying wire in a magnetic field is given by:
\[ \vec{F} = I \, \vec{dl} \times \vec{B} \]
- Here, \( \vec{dl} \) (the direction of current in Wire 2) is upward, and \( \vec{B} \) (the magnetic field due to Wire 1) is inward. Using the right-hand rule for the cross product, the force on Wire 2 due to Wire 1 will be directed towards Wire 1.

4. **Determine the Magnetic Field Created by Wire 2**:
- Now, we analyze the situation from the perspective of Wire 1. The current in Wire 2 is also upward, and using the right-hand thumb rule again, the magnetic field at the location of Wire 1 due to Wire 2 will also be directed inward.

5. **Calculate the Force on Wire 1 Due to Wire 2**:
- Using the same formula \( \vec{F} = I \, \vec{dl} \times \vec{B} \), where \( \vec{dl} \) is upward (current in Wire 1) and \( \vec{B} \) is inward (magnetic field due to Wire 2), we find that the force on Wire 1 due to Wire 2 is also directed towards Wire 2.

6. **Conclusion**:
- Since both wires exert forces on each other that are directed towards each other, we conclude that the force between two parallel wires carrying current in the same direction is **attractive**.

### Final Answer:
The force between two wires carrying current in the same direction is **attractive**.