Question

Using the right-hand screw rule, determine the direction of torque when a dipole moment \[\vec{p}\] is rotated toward an electric field \[\vec{E}\].

Options

• Opposite to \[\vec{E}\]

• Along the direction of \[\vec{p}\]

• Perpendicular to the plane containing \[\vec{p}\] and \[\vec{E}\]

• Along the direction of \[\vec{E}\]

Answer 1

According to the right-hand screw rule for cross products, if you curl your fingers from \[\vec{p}\] toward \[\vec{E}\], your thumb points along the direction of \[\vec{\tau}\] = \[\vec{p}\] × \[\vec{E}\]. This direction is always perpendicular to the plane containing both \[\vec{p}\] and \[\vec{E}\], following the properties of vector cross products.