Magnets and Magnetic Fields - Jamb Physics Past Questions and Answers

Question 46:

• JAMB 2009

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.

A. 5.60 v
B. 24.00 v
C. 0.24 v
D. 2.40 v

Question 47:

• JAMB 2010

In the diagram above, if the south-poles of two magnets strokes steel bar, the polarities at T and V will respectively be

A. South and north
B. North and south
C. North and north
D. South and south

Question 48:

• JAMB 2011

Which of the following is a property of steel?

A. It cannot retain its magnetism longer than iron
B. It can be used for making temporary magnets
C. It can be used for making permanent magnets
D. It can easily be magnetized and demagnetized

Question 49:

• JAMB 2012

Steel is more suitable for permanent magnet than iron because the former

A. Is easily demagnetized by shaing vigorously
B. Is an alloy of many metals
C. Is easily magnetized by alternating current through one cycle
D. Retains magnetism more than iron

Question 50:

• JAMB 2012

A conductor of length 2m carries a current of 0.8A while kept in a magnetic field of magnetic flux density 0.5T. The maximum force acting on it is

A. 0.2N
B. 0.8N
C. 3.2N
D. 8.0N