Two flat circular coils of wire are set up side by side, as shown in Figure. They are connected in series so that the same current flows around each, and in the same direction. Will the coils attract or repel one another? Explain your answer, first by describing the coils as electromagnets, and second by considering the forces between parallel currents. What will happen if the current is reversed in both coils?

 

 

Without looking at your textbook, make a list of the definitions for measuring the strength of a magnetic, an electric and a gravitational field. Compare your definitions with other students in your class.

Write a list of situations where magnetic fields are used in modern life .

Without looking at your textbook, make a list of the definitions for measuring the strength of a magnetic, an
electric and a gravitational field. Compare your definitions with other students in your class.

How will you use what you have learned in the future?

A wire carrying a current is placed at right angles to a uniform magnetic field of magnetic flux density$B$. When the current in the wire is / , the magnetic force that acts on the wire is $F$.

What is the force on the wire, placed in the same orientation, when the magnetic field strength is$2B$ and the current is $\frac{1}{4}$$?$

A  $\frac{F}{4}$  B $\frac{F}{2}$  C $F$   D $2F$

There is an electric current in a wire of mass per unit length$40 g{m}^{-1}$• The wire is placed in a magnetic field of strength $0.50$ T and the current is gradually increased until the wire just lifts off the ground. What is the value of the current when this happens?

$\left(a\right) 0.080A$

$\left(b\right) 0.20A$

$\left(c\right) 0.78 A$

$\left(d\right) 780A$

A current-carrying wire is placed in a uniform magnetic field.

(a) Describe how the wire should be placed to experience the
maximum force due to the magnetic field.

A current-carrying wire is placed in a uniform magnetic field.

(b) Describe how the wire should be placed to experience no force due to the magnetic field .

A current-carrying conductor placed at right angles to a uniform magnetic field experiences a force of$4.70\times {10}^{-3}N.$ Determine the force on the wire when, separately:

(a) the current in the wire is increased by a factor of$3.0$

A current-carrying conductor placed at right angles to a uniform magnetic field experiences a force of$4.70\times {10}^{-3}N.$ Determine the force on the wire when, separately:

(b) the magne tic flux density is halved