Fig. 1 shows a force experiment carried out during the design of a magnetic door lock. A straight copper conductor is held at 90 degrees to the field betwee...
Question 1 Report
Fig. 1 shows a force experiment carried out during the design of a magnetic door lock. A straight copper conductor is held at 90 degrees to the field between two magnet poles. It is connected to a variable power supply. The wire has a length of 0.080 m in the magnetic field. At one setting, the magnetic flux density is 0.50 T and the current is 3.0 A. The engineer uses the equation F = BIl to estimate the force. The conductor must remain still during each reading so that the force sensor gives a stable result.
(a) What does B represent in the equation F = BIl? [1]
(b) What is the force on the wire? [2]
(c) Which two conditions make this equation suitable for the wire in Fig. 1? [3]
Answer Details
(a) \(B\) is the magnetic flux density, also called magnetic field strength [1].
(b) Use \(F=BIl\):
\[F=0.50\times3.0\times0.080=0.12\text{ N}\]
Substitution gains [1] and \(0.12\text{ N}\) gains [1]. [2 marks]
(c) The equation applies because the wire carries a current [1], is in a magnetic field [1], and is at \(90^\circ\) to the field, with \(l\) being the length in the field [1]. [3 marks]
Download The App On Google Playstore
Everything you need to excel in your exams
