Chapter 21, Problem 6Q

(a)

To determine

To Explain: The direction or path of induced current in $R_A$ resistor when coil $B$ moves towards coil A.

Answer to Problem 6Q

The direction of induced current in $R_A$ resistor when coil $B$ : It moves toward coil $A$ .

Explanation of Solution

Introduction: Faraday examined quantitatively about what factors influence magnitude of EMF induced.

Faraday’s law of induction is the fundamental law of electromagnetism. According to this law,

  $EMF=-N\frac{\Delta {\varphi }_B}{\Delta t}$

According to the question, an induced current in $R_A$ is to right as coil $B$ is moved toward the coil $A$ .

When coil $B$ approaches coil $A$ , magnetic flux through acoil $A$ rises (here now additional magnetic field lines in a coil $A$ pointing to left direction).

Coil $A$ opposes this increment in the flux, and also, induced EMF produces current to generate magnetic field pointing to the right directionvia the centre of coil.

Current in Coil $A$ flowthrough $R_A$ towards right direction and will produce this opposing field.

(b)

To determine

To Explain: The direction of induced current in $R_A$ resistor when coil $B$ is moved away form $A$ .

Answer to Problem 6Q

The direction or path of induced current in the $R_A$ resistor when coil $B$ : It movesaway from coil $A$ .

Explanation of Solution

Introduction: Faraday examined quantitatively about what factors influence magnitude of EMF induced.

Faraday’s law of induction is the fundamental law of electromagnetism. According to this law,

  $EMF=-N\frac{\Delta {\varphi }_B}{\Delta t}$

According to the question, an induced current in $R_A$ is to left as coil $B$ is moved away from a coil $A$ .

When coil $B$ recedes from coil $A$ , magnetic flux overcoil $A$ decreases.

Coil $A$ attempts to oppose this decrement in flux, and also, induced EMF creates a current to produce magnetic field pointing to left direction through the centre of a coil.

Current in Coil $A$ through $R_A$ towards left direction will produce this opposing field.

(c)

To determine

The direction of induced current in $R_A$ resistor when resistance $R_B$ increases.

Answer to Problem 6Q

The direction of induced current in $R_A$ resistor when resistance $R_B$ is increased: It will be toward left.

Explanation of Solution

Introduction: Faraday examined quantitatively about what factors influence magnitude of EMF induced.

Faraday’s law of induction is the fundamental law of electromagnetism. According to this law,

  $EMF=-N\frac{\Delta {\varphi }_B}{\Delta t}$

According to the question, induced current in the $R_A$ resistor is to left direction as the $R_B$ resistance in coil $B$ is increased.

When base resistance $R_B$ increases, then current in coil $B$ will decrease accordingly. This decrement also decreases magnetic field that coil $B$ produces.