Chapter 29: Electromagnetic Induction

Question 1

What is magnetic flux ΦB in words and with an eq

Answer 1

ΦB is a meausre of the amount of magnetic field lines through a cross-sectional area

ΦB = ∫ B.dA (as vectors and ΦB scalar, unit Weber)

Question 2

What is the magnetic flux thorugha uniform B and non curved cross sectional area A

Answer 2

ΦB = B.A (as vectors) = BAcosθ

same as from high school

Question 3

Faraday’s law of induction in words

Answer 3

The induced emf in a circuit is equal (except for a change in sign) to the rate at
which magnetic flux through that circuit changes with time.

Question 4

Faraday’s law of induction in symbols

Answer 4

𝜀 = −𝑑Φ𝐵/𝑑t

Question 5

If Φ𝐵 is constant then what does that mean for the induced 𝜀

Answer 5

𝜀 = −𝑑Φ𝐵/𝑑t = 0

Question 6

Lenz’s law

Answer 6

The direction of the induced current in a loop will be in such a direction as to oppose the change that produced it.

Question 7

explain process of lenz’s law conceptually in steps via faraday’s law

Answer 7

Conceptually
Changing flux → Induced emf → Induced current → Induced magnetic
field

NOTE: be careful to distinguish between the original “source” field and the induced field.