Concepts Of Physics MCQ Edition [Volume 2]PhysicsElectromagnetic Induction
Consider the arrangement depicted in the figure. The wires P₁ Q₁ and P₂ Q₂ are forced to slide along the rails at an identical speed of 5 cm s ⁻¹ . Determine the electric current flowing through the 19 resistor if P₁ Q₁ travels towards the left while P₂ Q₂ travels towards the right.
Options
- A0.05 mA
- B0.2 mA
- C0.4 mA
- D0.1 mA
Correct answer
D. 0.1 mA
Step-by-step solution
The motional electromotive force (EMF) induced in a wire moving through a magnetic field is given by E = Bvl . Given: Magnetic field B = 1.0 T Speed of wires v = 5 cm s ⁻¹ = 0.05 m s ⁻¹ Length of wires l = 4 cm = 0.04 m The magnitude of the induced EMF in each wire is: E = 1.0 0.05 0.04 = 0.002 V = 2 mV Now, we determine the direction of the induced EMF using the right-hand rule (or v B ): For wire P₁ Q₁ moving towards the left, v is left and B is into the page. The force on positive charges is directed downwards (