• Induced emf (𝜀): The voltage developed in a circuit due to a change in the magnetic field.
• Magnetic Force due to Induced Current: F = BIL
  • B: Magnetic field strength
  • I: Induced current
  • L: Length of the rod
• Newton’s First Law & Rod Movement: A rod moves at constant speed when the net force acting on it is zero.
• Relation between emf and Energy: 𝜀 = Energy supplied in time Δt / Charge moved in Δt

• Imagine a rod moving to the right. The magnetic force from the induced current is like an opposing football player pushing the rod to the left! These two forces cancel each other out.
• When our rod is steady and cruising (constant velocity), it's like Newton's first law being in action. The force pushing the rod equals the opposing force.
• The energy we provide to the rod for moving is like giving it fuel - Energy = Force x Distance.

🌍 Real-world example: Imagine you're driving a car. To keep the car moving at a steady speed, you need to balance the accelerator (force to the right) and the brakes (force to the left). If they're balanced, you cruise smoothly!

• Magnetic field setup
  • Rod Length, L = 0.75m
  • Speed, v = 1.5ms⁻¹
  • Magnetic Field, B = 0.16T (Imagine this like the strength of a giant magnet coming out from your book/page!)
• Find the emf (Electromotive force): 𝜀 = BvL = 0.16 x 1.5 x 0.75 = 0.18V (Voilà! Your rod just got a charge!)
• Current and its direction
  • Using Ohm's law, I = 𝜀/R = 0.18/4.0 = 45mA.
  • Think of electrons as tiny ants. They move right, pushing the rod, but experience an upward force. This makes our ants (electrons) drift up, but the conventional current goes downwards. (Remember, ants might go one way, but the queen ant (current) decides the real direction!)
• Why need an external force?
  • Think of the rod on a treadmill. To keep it moving, you need to push it, or else the treadmill's force (magnetic force in our case) will push it back. This force ensures the rod keeps its pace!
• Rate of energy transfer
  • View 1: Electrical power in the circuit = 𝜀I = 0.18 x 0.045 = 8.1mW.
  • View 2: Like a superhero (external force) pushing the rod. Force F = BIL. Power = Force x speed = 8.1mW.