Fleming's hand rules – identify what the left-hand rule gives In electromagnetism, Fleming's left hand rule is applied to determine which of the following directions in a motor or current-carrying conductor placed in a magnetic field?

Introduction / Context:Fleming's left and right hand rules provide quick mnemonics for cross-product directions in electromagnetism. The left hand rule is associated with motor action (force), while the right hand rule relates to generator action (induced emf). Knowing which is which avoids errors in machinery and actuator design.

Given Data / Assumptions:

• Conductor carrying current I is placed in a magnetic field B.
• Force direction follows Lorentz force F = I (L × B).
• Hands mnemonic: First finger → field (B), seCond finger → current (I), thuMb → motion (Force).

Concept / Approach:

Fleming's left hand rule maps orthogonal directions: index finger for magnetic field, middle finger for conventional current, and thumb for the resulting force (motion). This directly answers problems in DC motors and moving-coil instruments where current flows in a magnetic field.

Step-by-Step Solution:

Verification / Alternative check:

Using vector cross product F = I (L × B) yields the same orientation as the left hand rule, confirming consistency between mnemonic and mathematics.

Why Other Options Are Wrong:

Direction of induced emf uses the right hand rule (generator rule); flux in a solenoid and field due to a straight conductor are found via right-hand grip/biot–savart, not Fleming's left hand rule.

Common Pitfalls:

Confusing left (motor) with right (generator) rules; mixing conventional current direction with electron flow.

Final Answer:

direction of force on a current carrying conductor