Download Magnetic Flux

SMJK CHUNG HWA, KOTA BHARU
Chapter 22 (1) Magnetic Flux
1. A small surface of area 10 mm2 inside a uniform magnetic field of strength 0.50 T is inclined at
an angle of  to the direction of the field. Determine the magnetic flux through the surface if
a)  = 00
b)  = 300
c)  = 900
Ans : a) 0 Wb
b) 2.5 X 10-6 Wb
c) 5 X 10-6 Wb
2. A circular coil has 10 turns and diameter 2.0 cm. It is placed in a uniform magnetic field of
strength 300 mT. The plane of the coil and the direction of the field make an angle of 30 0.
Determine the magnetic flux linkage through the coil.
Ans : 4.17 X 10-4 Wb
3. A circular coil is placed in a uniform magnetic field with its plane perpendicular to the
direction of the field. Suggest ways which can be employed to reduce the magnetic flux
linkage through the coil by 20%.
Ans : i)  = 53.10
ii) B’ = 0.8 B
iii) d’ = 0.89d
4. A circular coil of 20 turns and diameter 10 cm is
wound tightly round the middle portion of a long
solenoid, as shown in the diagram. A current of 2 A
flows through the solenoid, which has 500 turns per
metre. Determine the magnetic flux through the
coil.
Coil
Solenoi
d
Ans : 1.97 X 10-4 Wb
5. The area of the plane of a circular coil with 10 turns is 2.0 X 10 -3 m2. It is placed in a magnetic
field of strength 200 mT whose direction makes an angle of 200 with the plane of the coil.
Determine the change of flux if
a) The magnetic field strength changes to 500 mT.
b) The angle changes to 500 by rotating the coil.
Ans : a) 2.05 X 10-3 Wb
b) 1.72 X 10-3 Wb