A 1 metre long conductor carries a current of 40A at right angles to a magnetic field of 100×10-3 Tesla. The force on the conductor is:

Correct option is A

​$$\textbf{Explanation:} \text{The force } F \text{ on a conductor in a magnetic field is given by the equation:}$$​​$$F = B \cdot I \cdot L$$

$$\textbf{where:}$$

$$\begin{array}{ll}\bullet \quad B \text{ is the magnetic field strength (in Tesla),} \\\bullet \quad I \text{ is the current (in Amperes),} \\\bullet \quad L \text{ is the length of the conductor (in meters).}\end{array}$$

$$\textbf{Given:}$$

$$\begin{array}{ll}\bullet \quad B = 100 \times 10^{-3} \text{ Tesla} = 0.1 \text{ Tesla}, \\\bullet \quad I = 40 \text{ A}, \\\bullet \quad L = 1 \text{ m}.\end{array}$$

$$F = 0.1 \text{ T} \times 40 \text{ A} \times 1 \text{ m} = 4 \text{ N}$$​​