Exam #2 Circuits

Placing bulbs in a series.

-Increasing the number of bulbs decreases the brightness of the bulbs. -The resistance increases. In a series circuit, adding bulbs increases the resistance in the circuit. -Increasing the resistance decreases the current. A complete circuit requires the electrons to move from the negative terminal of the battery to the positive terminal. When one bulb is unscrewed it opens the circuit preventing a complete circuit and the electrons cannot return to the battery.

Placing batteries in a series.

-The bulbs become brighter when increasing the number of cells. -Increasing the number of cells increases the current in the circuit. -Increasing the number of cells increases the voltage (for cells in series the voltage is additive). -The resistance is determined by the number of bulbs. The resistance in the circuit remains unchanged.

Batteries placed in parallel.

-To get the most light from two cells and two bulbs you would connect the batteries in series and the bulbs in parallel. -To get the least light from two cells and two bulbs you would connect the batteries in parallel and the bulbs in series. -To get the longest life time from two cells and two bulbs you would connect the batteries in parallel and the bulbs in series.

Placing bulbs in Parallel

-Two bulbs in parallel are brighter than two bulbs in series. -In a parallel circuit each bulb is in its own circuit. As bulbs are added the resistance in the circuit decreases since each circuit is another pathway for electrons to move from one end of the circuit to the other.

If 6V were impressed across the circuit in question in question 26, and the voltage across the first lamp were 2 V, what would be the voltage across the second lamp.

4 v.

Batteries in a parallel?

A bulb connected to two cells in series is brighter than connected two to cells in a parallel. A bulb connected by two cells in parallel is equally bright as when connected to one cell. Two cells in series produce a brighter bulb, but will las as long as a single battery.

Simple Circuit

A complete conducting path for an electric current -When the circuit is connected to a battery, electrons flow from the negative terminal of the battery, through one or more electrical devices, and then back to the positive terminal of the battery.

Resistance

A resistance to the electrons flowing through the wire. -As the number of devices placed within one series circuit increases, the resistance also increases. -In a parallel circuit, as electrical devices are added the resistance decreases.

Which has the greater resistance, a thick wire or a thin wire of the same length?

A thin wire.

Sometimes you hear someone say that a particular appliance "uses up" electricity. what is tit that the appliance actually consumes, and what becomes of it?

An electric device does not "use up" electricity, but transforms it from one form to another.

As more lines are opened at a fast-food restaurant, the resistance to the motion of people trying to get served is reduced. How is this similar to what happens when more branches are added to a parallel circuit.

As more branches (circuits) are added in a circuit, there is less resistance to the overall from of charge (current).

Series Circuit

Connecting any electrical device one after the other -Placing the batteries in series results in the voltages of the batteries to be added.

How does the total current through the branches of a parallel circuit compare with the current through the voltage source?

Current in each branch is less than the current at the source. Current is distributed.

Current

Flows through the circuit depends upon the number of electrons flowing through the circuit per second. -Increasing the voltage also increases the current in the circuit. -An increase of current can be observed when the brightness of the bulb increases.

What happens by putting bulbs in series?

Increasing the number of bulbs in a series circuit decreases the brightness of the bulbs. In a series circuit, the voltage is equally distributed among all the bulbs. Unscrewing a bulb puts out the entire series.

What happens as you add another battery in a series circuit?

Increasing the voltage increases the brightness of the bulb.

Only a small percentage of the electric energy fed into a common lightbulb is transformed into light. What happens to the rest?

Most of the energy, typically 95%, of the electrical energy in an incandescent lamp goes directly to heat. Heat energy is the graveyard of all forms of energy.

What is the unit of electrical resistance?

Ohms

In circuit consisting of two lamps connected in series, if current in one lamp is 1Ampere, what is the current in the other lamp?

Same, I amp.

Does a battery produce dc or ac? Does the generator at power station produce Dc or Ac?

The batter produces Direct current and the generator produces Alternative current.

What is the effect on current through a circuit of steady resistance when the voltage is doubled? what if both voltage and resistance are doubled?

The current is doubled. If voltage and resistance are doubled then no charge.

As more and more bulbs are connected in series to a flashlight battery, what happens to the brightness of each bulb? Assuming that the hearing inside the batter is negligible, what happens to the brightness of each bulb when more and more bulbs are connected in parallel?

As more bulbs are connected in series, more resistance is added to the single circuit path and the resulting current produced by the battery is diminished. This is evident in the dimmer light from the bulbs. On the other hand, when more bulbs are connected to the battery in parallel, the brightness of the bulbs is practically unchanged. This is because each bulb in effect is connected directly to the battery with no other bulbs in its electrical path to add to its resistance. Each bulb has its own current path.

What happens to the brightness of light emitted by a lightbulb when the current in it increases?

As the current in the filament of a lightbulb increases, the bulb glows brighter

Are automobile headlights wired in parallel or in series what is your evidence?

Auto headlights are wired in parallel. Then when one burns out, the other remains lit

What happens when placing bulbs in parallel?

Bulbs in parallel are brighter than bulbs in series. In a parallel circuit the voltage for each bulb is the same as the voltage in the circuit. Unscrewing one bulb has no effect on the other bulb. (It has more than one way to go.)

Consider a pair of flashlights bulbs connected to a battery. Do they glow brighter if they are connected in series or in parallel? Does the batter run down faster if they are connected in series ore parallel?

Bulbs will glow brighter when connected in parallel, for the voltage of the battery is impressed across each bulb. When two identical bulbs are connected in series, half the voltage of the battery is impressed across each bulb. The battery will run down faster when the bulbs are in parallel.