Explain how Lenz’s law illustrates the principle of energy conservation.

Rapidly inserting the north pole of a bar magnet into a coil of wire connected to a galvanometer causes the needle of the galvanometer to deflect to the right. What will happen to the needle if you do the following? let the magnet sit at rest in the coil

Rapidly inserting the north pole of a bar magnet into a coil of wire connected to a galvanometer causes the needle of the galvanometer to deflect to the right. What will happen to the needle if you do the following? pull the magnet out of the coil

A generator supplies $5.0 \times 10^{3}$ kW of power. The output emf is 4500 V before it is stepped up to 510 kV. The electricity travels 410 mi ($6.44 \times 10^{5}$ m) through a transmission line that has a resistance per unit length of $4.5 \times 10^{−4} \Omega / \mathrm{m}$. How much power would be lost through transmission if the generator’s output emf were not stepped up? What does this answer tell you about the role of large emfs (voltages) in power transmission?

A generator supplies $5.0 \times 10^{3}$ kW of power. The output emf is 4500 V before it is stepped up to 510 kV. The electricity travels 410 mi ($6.44 \times 10^{5}$ m) through a transmission line that has a resistance per unit length of $4.5 \times 10^{−4} \Omega / \mathrm{m}$. How much power is lost through transmission of the electrical energy along the line?

Which of the following correctly describes the composition of an electromagnetic wave? A. a transverse electric wave and a magnetic transverse wave that are parallel and are moving in the same direction, B. a transverse electric wave and a magnetic transverse wave that are perpendicular and are moving in the same direction, C. a transverse electric wave and a magnetic transverse wave that are parallel and are moving at right angles to each other, D. a transverse electric wave and a magnetic transverse wave that are perpendicular and are moving at right angles to each other.

A pair of adjacent coils has a mutual inductance of 1.06 H. Determine the average emf induced in the secondary circuit when the current in the primary circuit changes from 0 A to 9.50 A in a time interval of 0.0336 s.

The alternating emf of a generator is represented by the equation emf=(245 V) sin 560t, in which emf is in volts and t is in seconds. Use these values to find the frequency of the emf and the maximum emf output of the source.

The potential difference in the lines that carry electric power to homes is typically 20.0 kV. What is the ratio of the turns in the primary to the turns in the secondary of the transformer if the output potential difference is 117 V?

A transformer has 22 turns of wire in its primary and 88 turns in its secondary. If 110 V ac is applied to the primary, what is the output potential difference?

A transformer has 22 turns of wire in its primary and 88 turns in its secondary. Is this a step-up or step-down transformer?

A coil of 325 turns and an area of $19.5 \times 10^{−4} \mathrm{m}^{2}$ is removed from a uniform magnetic field at an angle of $45^{\circ}$ in 1.25 s. If the induced emf is 15 mV, what is the magnetic field’s strength?

A student attempts to make a simple generator by passing a single loop of wire between the poles of a horseshoe magnet with a $2.5 \times 10^{−2}$ T field. The area of the loop is $7.54 \times 10^{−3} \mathrm{m}^{2}$ and is moved perpendicular to the magnetic field lines. In what time interval will the student have to move the loop out of the magnetic field in order to induce an emf of 1.5 V? Is this a practical generator?

Why is a longer antenna needed to produce a low-frequency radio wave than to produce a high-frequency radio wave?