Question

Which of the following statements are true concerning electromagnetic induction? Check all that apply. Check all that apply. It is possible to induce a current in a closed loop of wire by change the orientation of a magnetic field enclosed by the wire. It is possible to induce a current in a closed loop of wire by changing the strength of a magnetic field enclosed by the wire. It is possible to induce a current in a closed loop of wire without the aid of a power supply or battery. It is possible to induce a current in a closed loop of wire located in a uniform magnetic field without rotating the loop and without changing the loop shape. It is possible to induce a current in a closed loop of wire located in a uniform magnetic field by either increasing or decreasing the area enclosed by the loop.

Answer 1

Answer:

The statements that apply are:

• It is possible to induce a current in a closed loop of wire by change the orientation of a magnetic field enclosed by the wire.

• It is possible to induce a current in a closed loop of wire by changing the strength of a magnetic field enclosed by the wire.

• It is possible to induce a current in a closed loop of wire without the aid of a power supply or battery.

• It is possible to induce a current in a closed loop of wire located in a uniform magnetic field by either increasing or decreasing the area enclosed by the loop.

Explanation:

Faraday's law says that the induced emf $\varepsilon$ is equal to

$\varepsilon = N \dfrac{d\Phi_ B}{dt },$

where N is the number of turns, and $\Phi_B$ is the magnetic flux  through the loop:

$\Phi_B = BA cos(\theta)$;

therefore,

$\varepsilon = N \dfrac{d(BAcos(\theta))}{dt },$

which means emf will be induced in a coil whenever the magnetic field $B$, the area $A$, or the angle $\theta$ is changed. Given this, let us look at each of the statements one by one:

(1). It is possible to induce a current in a closed loop of wire by changing the orientation of a magnetic field enclosed by the wire. ( Yes. This changes $\theta$)

(2). It is possible to induce a current in a closed loop of wire by changing the strength of a magnetic field enclosed by the wire. ( Yes. This changes $B$)

(3). It is possible to induce a current in a closed loop of wire without the aid of a power supply or battery. (Yes, a changing magnetic field can also do the job)

(4).  It is possible to induce a current in a closed loop of wire located in a uniform magnetic field without rotating the loop and without changing the loop shape.  (Nope. This does not change $B,A,$ or $\theta$.)

(5). It is possible to induce a current in a closed loop of wire located in a uniform magnetic field by either increasing or decreasing the area enclosed by the loop. (Yep. This changes $A$)

Thus, the statements that apply are (1), (2), (3), and (5).