Electric Circuit Test

T/F A fuse or circuit breaker used in a circuit is usually inserted in parallel

...

T/F A schematic diagram is a simple blocked out

T

Fuses and circuit breakers are used to

all of the above

In order to form an electric circuit you need to have

all of the above

When one light bulb in a series circuit containing several light bulbs burn out none

of the other bulbs with light up

When two light bulbs are connected in a series, the

same amount of current always flows through the bulbs

In simple parallel circuit the

voltage across each branch is always the same

Problems: 1. What is the equivalent resistance of a 30ohm and a 20ohm resistor connected in parallel? 2. Two identical resistors in parallel have an equivalent resistance of 7 ohms. If the same resistors were instead connected in series, what would be the equivalent resistance? 3. A 30 V potential difference is applied across a series combination of 8 ohm resistor and a 3 ohm resistor. What is the current in the 8 ohm resitro. 4. A 60 V potential difference is applied across a parallel combination of 10 ohm resistor and a 20 ohm resistor. What is the current in the 10 ohm resitro. 5. A 20 V potential difference is applied across a parallel combination of 60 ohm resistor and a 10 ohm resistor. What is the current in the 10 ohm resitro. 6. A 2.0 ohm resistor is connected in sereris with a 20 V battery and a three branch parallel network with branches whose reistnce are 6 ohms each. Ignoring the batteries internal resistance what is the current in the battery 7. A 50 V battery is connected across a 10 ohm resistor and produces a current of 4.5 A. What is the internal resistance of the battery?

1. 1/ Rtotal= 1/R+ 1/R 1/30 + 1/20 = 5/60 = 60/5 = 12 ohm 2. 1/ Rtotal= 1/R+ 1/R 1/7 = 2/R R = 14 (14)(2) = 28 ohms 3. I = V/C I = 30/11 x = 2.7 amp 4. I = V/C I= 60/10 I = 6 amp 5. I = V/C I= 20/10 I = 2 amp 6. 1/ Rt = 3/6 I = V/R I = 20/4 = 5 amps 7. I = V/R 4.5 = 50/x x= 11.11 - 10 = 1.11 ohms

The total resistance of a 6 ohm resistor and a 12 ohm resistor in parallel is

1/ Rtotal = 1/6 + 1/12 = 1/4 then fill 4

A 60 W light bulb and a 100 W light bulb are both connected in parallel to a 120 V outlet. Which light bulb has more current in it?

100 W

T/F In a parallel circuit, current in each branch is the same

F

The current through two identical light bulbs connected in series is .25 A. The total voltage across both bulbs is 120 V. The resistance os a single bulb is

I = V/R .25 = 120/x x= 240

T/F In a series circuit, the total voltage drop across a series of resistors is the sum of voltage drops across each ind resistor

T

T/F In order to prevent overloading, fuses are inserted in the circuit

T

T/F When a light bulb are connected in series, all carry the same current regardless of their resistance

T

T/F When resistors are arranged in parallel, thier overall resistance is less than that of the smallest resistor

T

In a simple parallel circuit

all of the aboce

Two lamps, one with a thick figment and one with a thin filament, are connected in a parallel to a battery. The voltage is greater across the lamp with the

both are the same

When one light bulb in a parallel circuit containing several light bulb burns out, the other bulbs

burn the same as before

As more lamps are put into series circuit, the overall current in the circuit

decreases

A 60 W light bulb is connected to a 12 V battery. When another 60 W bulb is connected in parallel with the first bulb, the output energy

doubles

A closed circuit is a circuit in which charge can

flow

As more lamps are put into parallel circuit, the overall current in the circuit

increases

When resistors are put in series next to each other, their overall resistance is

large than the resistance of one of the resistors

Compared to the resistance of two resistors connected in series, the same two resistors connected in parallel have

less resistance

When resistors are put in parallel with each other their overall resistance is

smaller than the resistance of any other resistors

A short circuit occurs when

the positive wire is connected directly to the negative wire

Two lamps, one with a thick figment and one with a thin filament, are connected in a parallel to a battery. The current is greater across the lamp with the

thick filament

Two lamps, one with a thick figment and one with a thin filament, are connected in a series to a battery. The voltage is greater across the lamp with the

thin figment