A straight, rigid copper rod of length 250 mm is suspended horizontally in a uniform horizontal magnetic field. The rod is aligned perpendicular to the magnetic field lines. During a calibration test, the current in the rod is increased by 1.2 A, which causes the downward magnetic force on the rod to increase by 4.5 × 10-2 N.
What is the magnetic flux density of the field?
1.5×10−4 T1.5 \times 10^{-4}\text{ T}1.5×10−4 T
9.4×10−3 T9.4 \times 10^{-3}\text{ T}9.4×10−3 T
1.5×10−1 T1.5 \times 10^{-1}\text{ T}1.5×10−1 T
6.7 T6.7\text{ T}6.7 T
66 exam-style questions on AQA A Level Physics Magnetic fields (A-level only), covering Magnetic flux density (A-level only), Moving charges in a magnetic field (A-level only), Magnetic flux and flux linkage (A-level only), Electromagnetic induction (A-level only), Alternating currents (A-level only), and The operation of a transformer (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.