JAMB - Physics (2004 - No. 14)
A steady current of 2A flows in a coil of emf 12V for 0.4s. A back emf of 3V was induced during this period. The stored energy in the loop that can be utilized is
9.6J
2.4J
12.0J
7.2J
คำอธิบาย
Energy stored = Ivt = current x back e.m.f x time
= 2 x 3 x 0.4
= 2.4J
= 2 x 3 x 0.4
= 2.4J