To determine the magnetic force acting on a straight conductor carrying a current in a magnetic field, we can use the formula: \[ F = B \cdot I \cdot L \cdot \sin(\theta) \] Where: - \( F \) is the magnetic force (in Newtons, N) - \( B \) is the magnetic field strength (in Teslas, T) - \( I \) is the current (in Amperes, A) - \( L \) is the length of the conductor within the magnetic field (in meters, m) - \( \theta \) is the angle between the magnetic field and the direction of the current (in degrees or radians) ### Given Data: - Current, \( I = 5 \, \text{A} \) - Magnetic field strength, \( B = 0.2 \, \text{T} \) - Length of the conductor, \( L = 0.3 \, \text{m} \) - Angle, \( \theta = 90^\circ \) ### Step-by-Step Calculation: 1. **Identify the sine of the angle**: Since the angle \( \theta \) is \( 90^\circ \), we know that: \[ \sin(90^\circ) = 1 \] 2. **Substitute the values into the formula**: \[ F = B \cdot I \cdot L \cdot \sin(\theta) \] \[ F = 0.2 \, \text{T} \cdot 5 \, \text{A} \cdot 0.3 \, \text{m} \cdot 1 \] 3. **Perform the multiplication**: - First, calculate \( B \cdot I \): \[ 0.2 \, \text{T} \cdot 5 \, \text{A} = 1.0 \, \text{T} \cdot \text{A} \] - Next, multiply by \( L \): \[ 1.0 \, \text{T} \cdot \text{A} \cdot 0.3 \, \text{m} = 0.3 \, \text{N} \] 4. **Final Result**: \[ F = 0.3 \, \text{N} \] ### Conclusion: The magnetic force acting on the conductor is **0.3 N**. Therefore, the correct option is **A**. ### Explanation of Other Options: - **Option B (0.6 N)**: This value could arise if the current or the length of the conductor were doubled, but with the given values, it does not apply. - **Option C (0.9 N)**: This value is incorrect as it suggests a higher force than calculated. It could be a result of miscalculating the multiplication or misunderstanding the angle. - **Option D (1.2 N)**: This option is also incorrect and would imply an even larger force, which is not supported by the given parameters. ### Common Pitfalls: - **Forgetting the sine function**: Always remember to include the sine of the angle, especially if it is not \( 90^\circ \) or \( 0^\circ \). - **Misreading units**: Ensure that all units are consistent (e.g., T for magnetic field, A for current, m for length). - **Calculation errors**: Double-check each step of multiplication to avoid simple arithmetic mistakes. ### Revision Summary: - Use the formula \( F = B \cdot I \cdot L \cdot \sin(\theta) \) to calculate magnetic force. - Ensure to substitute the correct values and calculate step-by-step. - Remember that \( \sin(90^\circ) = 1 \) simplifies the calculation. - Check your final answer against the options provided to ensure accuracy.