JAMB - Physics (2009 - No. 29)
A band of 500 rectangular loops of wire of area 20 cm by 20 cm, encloses a region of magnetic field which charges from 1.0T to 0.4T within 5 seconds, calculate the induced e.m.f.
5.60 v
24.00 v
0.24 v
2.40 v
Giải thích
Number of tunes, n = 500
Area, A = 0.2m + 0.2m = 0.4m2
change of flux density A B
= 1.0 - 0.4 = 0.6T
Tune, t = 5 su
Induced emf, ξ = (AB AN)/AT
(0.6 x 0. 04 x 500)/5
= 2.4v
Area, A = 0.2m + 0.2m = 0.4m2
change of flux density A B
= 1.0 - 0.4 = 0.6T
Tune, t = 5 su
Induced emf, ξ = (AB AN)/AT
(0.6 x 0. 04 x 500)/5
= 2.4v