Download 1. A simple series circuit contains a resistance R and an ideal

1. A simple series circuit contains a resistance R and an ideal battery. If a second
resistor is connected in parallel to R
(a) the current through R will decrease
(b) the voltage across R will decrease
(c) the total current in the circuit will increase
(d) the rate of heat production in R will increase
(e) the equivalent resistance of the circuit will increase
2. Two pieces of copper wire have the same length, but wire A has a square cross
section of width S whereas wire B has a circular cross section of diameter S.
Then, (a) the resistance of both wires is the same
(b) the resistivity of both wires is the same
(c) the resistance of A is greater than that of B
(d) the resistivity of A is greater than that of B
(e) both resistance and resistivity of A and B are the same
3. The potential difference across the ends of a wire is doubled in magnitude. If
ohm’s law is obeyed, the resistance of the wire is (a) not changed
(b) ½ of its original value
(c) twice the original value
(d) increased by a factor of four
(e) decreased by a factor of four
4. The current through a certain heater wire is found to be fairly independent of its
temperature. If the current through the heater is doubled, the amount of energy
delivered by the heater is a given time interval will
(a) increase by a factor for two
(b) increase by a factor for four
(c) decrease by a factor for two
(d) increase by a factor for eight
(e) decrease by a factor for four
5. Two wires A and B and a variable resistor, R, are connected in series to a battery.
If the resistance of R is increased, then
(a) the current through A and B will increase
(b) the voltage through A and B will increase
(c) the voltage across the entire circuit will increase
(d) the current across the entire circuit will increase
(e) the power used by the entire circuit will increase
6. A battery is manufactured to have an emf of 24 V, but the terminal voltage is only
22 V when the battery is connected across a 7.5 ohm resistor. The internal
resistance of the battery is
(a) 3.2 ohms
(b) 0.27 ohms
(c) 1.2 ohms
(d) 0.75 ohms
(e) 0.68 ohms
7. Which of the following statements is true concerning capacitors of unequal
capacitance connected in series?
(a) Each capacitor holds a different amount of charge.
(b) The equivalent capacitance of the circuit is the sum of the individual capacitances.
(c) The total voltage supplied by the battery is the sum of the voltages across each
capacitor.
(d) The total positive charge in the circuit is the sum of the positive charges on each
capacitor.
(e) The total voltage supplied by the battery is the equal to the average voltages
across all the capacitors.
8. A simple RC circuit consists of a 1 µF capacitor in series with a 3000 Ω resistor, a 6
V battery, and an open switch. Initially the capacitor is uncharged. How long after the
switch is closed will the voltage across the capacitor be 3.8 V?
(a) 3 x 109 S
(b) 3 s
(c) 3 x 10-9 s (d) 0.003 s
(e) 3 x 10-8 s
9. Battery A has a relatively high internal resistance, whereas battery B has a low
internal resistance. If both batteries provide the same current to some external circuit,
then
(a) battery A is warmer to the touch than battery B
(b) battery B is warmer to the touch than battery A
(c) battery A is cooler to the touch than battery B
(d) both batteries are equally warm to the touch
(e) the emf of each battery must be known in order to contrast the batteries’ warmth
to the touch.
10. Two copper wires have the same volume, but wire 2 is 10% longer than wire 1. The
ratio of the resistances of the two wires R2/R1 is
(a) 1.2
(b) 0.82
(c) 1.1
(d) 0.91
(e) 1.0
11. Two resistors have the same power dissipated in them. The potential drop across
resistor A is twice that across resistor B. If the resistance on resistor B is R, then the
resistance of A is
(a) R
(b) 2 R
(c) R/2
(d) 4 R
(e) R/4
12. The conservation of energy is an electrical circuit is closely related to
(a) ohm’s law
(b) the junction rule
(c) the loop rule
(d) ampere’s law
(e) gauss’ law
13. When a battery goes from “good” to “bad” , this means that
(a) the voltage is used up
(b) the internal resistance has increased
(c) the internal resistance has decreased
(d) the voltage is used up and the internal resistance has increased
(e) the voltage is used up and the internal resistance has decreased
14. Conduction electrons move to the right in a certain wire. This indicates that:
(a) the current density and the electric field both point right
(b) the current density and the electric field both point left
(c) the current density points right and the electric field points left
(d) the current density points left and the electric field points right
(e) the current density points left but the direction of the electric field points is
unknown
15. The current density is the same in two wires. Wire A has twice the free-electron
concentration of wire B. The drift speed of the electrons in A is
(a) twice that of electrons in B
(b) four times that of electrons in B
(c) half that of electrons in B
(d) one-fourth that of electrons in B
(e)the same as that of electrons in B
16. Of the following, the copper conductor with the least resistance is
(a) thin, long and hot
(b) thick, short and cool
(c) thick, long and hot (d) thin, short and cool
(e) thin, short and hot
17. You wish to double the rate of energy dissipation in a heating device. You could:
(a) double the potential difference keeping the resistance the same
(b) double the current keeping the resistance the same
(c) double the resistance keeping the potential difference the same
(d) double the resistance keeping the current the same
(e) double both the potential difference and the current
18. It is better to send 10,000 kW of electric power long distances at 10,000V rather than
at 200V because:
(a) there is less heating in the transmission wires
(b) the resistance of the wires is less at high voltages
(c) more current is transmitted at high voltages
(d) the insulation is more effective at high voltages
(e) the iR drop along the wires is greater at high voltage
19. The emf of a battery is equal to its terminal potential difference
(a) always
(b) only when the battery is being charged
(c) only when a large current is in the battery
(d) only when there is no current in the battery
(e) never
20.Two 110 light bulbs, one “25 W” and the other “100 W”, are connected in series at a
110 V source. Then,
(a) the current in the 100 W bulb is greater than that in the 25 W bulb
(b) the current in the 100 W bulb is less than that in the 25 W bulb
(c) both bulbs will light with equal brightness
(d) each bulb will have a potential difference of 55 V
(e) none of the above