Electricity 101 - Conductors and Insulators (Part 1 of 6)

Current Electricity Animation

Chapter 21, Problems 4, 7. A single loop of wire ...

PHYSICS OLIMPIADS

Chapter 21, Problem 4. A single loop of wire with an area of x₁ m² is in a uniform magnetic field that has an initial value of x₂ T, is perpendicular to the plane of the loop, and is decreased with the constant rate of x₃ T/s.
(a) What emf is induced in this loop?

(b) If the loop has a resistance of x₄ Ω, find the current induced in the loop.

Chapter 21, problem 7. A closely wound rectangular coil of N turns has dimensions of x₁ cm by x₂ cm. The plane of the coil is rotated from a position where it makes an angle of x₃ᵒ with a magnetic field of x₄ T to a position perpendicular to the field. The rotation takes x₅ s.
What is average emf induced on the coil?

Magnetic Field and Magnetic Forces: Problems

Chapter 20, problem 31.

A rectangular x₁ cm by x₂ cm circuit carrying an x₃ A current is oriented with its plane parallel to a uniform x₄ T magnetic field (Figure 20.62, page 693).
(a) Find the magnitude and direction of the magnetic force on each straight segment of this rectangular circuit.
Illustrate your answers with clear diagrams.
(b) Find the magnitude of the net force on the entire circuit.
(c)  Find the magnitude of the net torque on the entire circuit.

Chapter 20, problem 57.

A circular metal loop is x₁ cm in diameter.
How large a current must flow through this metal so that the magnetic field at its center is equal to the magnetic field of x₂ T?

Chapter 20, problem 62.

Two circular concentric loops of wire lie on a tabletop, one inside the other.
The inner loop has a diameter of x₁ cm and carries a clockwise current of x₂ A,
as viewed from above, and the outer wire has a diameter of x₃ cm.
What must be the magnitude and direction (as viewed from above) of the current in the outer loop so that the net magnetic field due to this combination of loops is zero at the common center of the loops?

Chapter 20, problem 64.

A solenoid contain N coils of very thin wire evenly wrapped over a length of x₁ cm.
Each coil is x₂ cm in diameter.
If yhis solenoid carries a current of x₃ A, what is the magnetic field at its center?

Math Pictures and Formulae