⚡ Average EMF Induced in a Rectangular Coil
📘 Question:
A rectangular coil with 80 turns and dimensions 25 cm × 15 cm is placed in a magnetic field that drops from 0.75 T to 0.25 T in 0.20 s. The field is perpendicular to the plane. What is the average emf induced?
✅ Step-by-Step Explanation:
🔹 Step 1: Given Values
- Turns (N) = 80
- Length = 0.25 m
- Width = 0.15 m
- Bi = 0.75 T
- Bf = 0.25 T
- Δt = 0.20 s
🔹 Step 2: Area of the Loop
A = 0.25 × 0.15 = 0.0375 m²
🔹 Step 3: Magnetic Flux Change
ΔΦ = (Bf – Bi) × A = (0.25 – 0.75) × 0.0375 = -0.01875 Wb
🔹 Step 4: Apply Faraday’s Law
EMFavg = |N × ΔΦ / Δt| = |80 × (-0.01875) / 0.20| = 7.5 V
🎯 Final Answer:
The average induced EMF is 7.5 V.