A single circular conducting loop of radius rests flat on a horizontal table
PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A single circular conducting loop of radius 4.0cm rests flat on a horizontal table. A spatially uniform magnetic field is directed vertically upward through the loop and varies with time according to
B(t)=0.75(1−e−0.40t)T,
where t is measured in seconds.
(a) Describe qualitatively how the magnetic flux through the loop changes from t=0 to very large t. Discuss both its magnitude and whether it approaches a limiting value.
(b) As viewed from above the table, indicate whether the induced current flows clockwise or counter-clockwise while the magnetic field is increasing. Justify your answer using appropriate physical reasoning.
(c) Determine what happens to the magnitude of the induced emf as t→∞. Explain why this behavior occurs without performing an explicit numerical calculation.