ANSWERS TO QUESTIONS Q1. THROUGH Q17.
A1. The henry, H.

A2. Magnetic field.

A3. Inductance is the property of a coil (or circuit) which opposes any CHANGE in current.

A4. Induced emf is the emf which appears across a conductor when there is relative motion
between the conductor and a magnetic field; counter emf is the emf induced in a conductor
that opposes the applied voltage.

A5. The induced emf in any circuit is in a direction to oppose the effect that produced
it.

A6. No effect.

Inductance opposes any change in the amplitude of current.

A7. The numbers of turns in a coil.

The type of material used in the core.

The diameter of the coil.

The coil length.

The number of layers of windings in the coil.

Increases inductance.

Increases inductance.

Decreases inductance.

Increases inductance.

Increases inductance.

A8. Inductance causes a very large opposition to the flow of current when voltage is first
applied to an LR circuit; resistance causes comparatively little opposition to current at
that time. Zero. During current buildup, the voltage across the resistor gradually
increases to the same voltage as the source voltage; and during current decay the voltage
across the resistor gradually drops to zero.

A9.

A10. 1.71 amperes.

5 time constants.

2 time constants.

A11. Copper loss; hysteresis loss; eddy-current loss.

A12. Mutual inductance is the property existing between two coils so positioned that flux
from one coil cuts the windings of the other coil.

A13. When they are arranged so that energy from one circuit is transferred to the other
circuit.

A14. The ratio of the fines of force produced by one coil to the lines of force that link
another coil. It is never greater than one.

A15.

A16.

A17.