Chapter 19: DC Circuits
MCAT Study Guide



1.  

For resistors connected in series, which of the following will be the same for each of the resistors?
The current through.
The potential difference across.
The resistance of.
The power dissipated by.

2.  

If R1 = 2.0 and R2 = 6.0 , what is the equivalent resistance of the circuit?
1.5
4.0
8.0
12

3.  

If the potential difference across the dc source is 5.0 volts, and R2 = 10, what is the potential difference across R2?
0.50 V
2.0 V
5.0 V
50 V

4.  

The parallel combination of resistors A and B is connected to a voltage source. If the resistance of A is four times as great as the resistance of B, then the current through A must be
twice as great as that in B.
half as great as that in B.
four times as great as that in B.
one fourth as great as that in B.

5.  

If all the components of an electric circuit are connected in series, the physical quantity that is constant at all points in the circuit is the
voltage.
current.
resistance.
power.

6.  

The current through a resistor is measured as a function of the potential difference across the resistor for three individual resistors, the series combination of the three resistors and the parallel combination of the three resistors. The results of the five sets of measurements are shown in the figure at the right.

The parallel combination of the three resistors is represented by the curve labeled ___.
A
B
C
D
E

7.  

The current through a resistor is measured as a function of the potential difference across the resistor for three individual resistors, the series combination of the three resistors and the parallel combination of the three resistors. The results of the five sets of measurements are shown in the figure at the right.

The individual resistor which has the smallest resistance is represented by the curve labeled ___.
A
B
C
D
E

8.  

The current through a resistor is measured as a function of the potential difference across the resistor for three individual resistors, the series combination of the three resistors and the parallel combination of the three resistors. The results of the five sets of measurements are shown in the figure at the right.

The series combination of the three resistors is represented by the curve labeled ___.
A
B
C
D
E

9.  

In the circuit below and to the right R1 < R2 < R3 < R4 and each resistor has the same maximum power dissipation capability, Po. The potential difference across, the current through and the rate at which heat is being created within the jth resistor are Vj, Ij and Hj respectively.

V1 is ___ V4.
more than
less than
equal to
incomparable, without additional information, with

10.  

In the circuit below and to the right R1 < R2 < R3 < R4 and each resistor has the same maximum power dissipation capability, Po. The potential difference across, the current through and the rate at which heat is being created within the jth resistor are Vj, Ij and Hj respectively.

V2 is ___ V3.
more than
less than
equal to
incomparable, without additional information, with

11.  

In the circuit below and to the right R1 < R2 < R3 < R4 and each resistor has the same maximum power dissipation capability, Po. The potential difference across, the current through and the rate at which heat is being created within the jth resistor are Vj, Ij and Hj respectively.

V2 is ___ V4.
more than
less than
equal to
incomparable, without additional information, with

12.  

In the circuit below and to the right R1 < R2 < R3 < R4 and each resistor has the same maximum power dissipation capability, Po. The potential difference across, the current through and the rate at which heat is being created within the jth resistor are Vj, Ij and Hj respectively.

I2 is ___ I3.
equal to
more than
less than
incomparable, without additional information, with

13.  

In the circuit below and to the right R1 < R2 < R3 < R4 and each resistor has the same maximum power dissipation capability, Po. The potential difference across, the current through and the rate at which heat is being created within the jth resistor are Vj, Ij and Hj respectively.

I2 is ___ I1.
equal to
more than
less than
incomparable, without additional information, with

14.  

In the circuit below and to the right R1 < R2 < R3 < R4 and each resistor has the same maximum power dissipation capability, Po. The potential difference across, the current through and the rate at which heat is being created within the jth resistor are Vj, Ij and Hj respectively.

I1 is ___ I4.
equal to
more than
less than
incomparable, without additional information, with

15.  

In the circuit below and to the right R1 < R2 < R3 < R4 and each resistor has the same maximum power dissipation capability, Po. The potential difference across, the current through and the rate at which heat is being created within the jth resistor are Vj, Ij and Hj respectively.

H1 is ___ H4.
less than
equal to
more than
incomparable, without additional information, with

16.  

In the circuit below and to the right R1 < R2 < R3 < R4 and each resistor has the same maximum power dissipation capability, Po. The potential difference across, the current through and the rate at which heat is being created within the jth resistor are Vj, Ij and Hj respectively.

H3 is ___ H4.
less than
equal to
more than
incomparable, without additional information, with

17.  

In the circuit below and to the right R1 < R2 < R3 < R4 and each resistor has the same maximum power dissipation capability, Po. The potential difference across, the current through and the rate at which heat is being created within the jth resistor are Vj, Ij and Hj respectively.

H2 is ___ H3.
less than
equal to
more than
incomparable, without additional information, with

18.  

In the circuit below and to the right R1 < R2 < R3 < R4 and each resistor has the same maximum power dissipation capability, Po. The potential difference across, the current through and the rate at which heat is being created within the jth resistor are Vj, Ij and Hj respectively.

If the resistance of R1 was increased slightly, V4 would ___.
remain constant
decrease
increase
be unpredictable

19.  

In the circuit below and to the right R1 < R2 < R3 < R4 and each resistor has the same maximum power dissipation capability, Po. The potential difference across, the current through and the rate at which heat is being created within the jth resistor are Vj, Ij and Hj respectively.

If the resistance of R1 was increased slightly, V1 would ___.
remain constant
decrease
increase
be unpredictable

20.  

In the circuit at the right a single source of emf, E1, with internal resistance r1 is connected to a variable load resistance Rload > r.

If the resistance of the load was increased slightly, the current flowing through the load resistance would ___.
remain constant
increase
decrease
be impossible to predict

21.  

In the circuit at the right a single source of emf, E1, with internal resistance r1 is connected to a variable load resistance Rload > r.

If the resistance of the load was decreased slightly, the potential difference across the terminals of the emf would ___.
remain constant
increase
decrease
be impossible to predict

22.  

In the circuit at the right a single source of emf, E1, with internal resistance r1 is connected to a variable load resistance Rload > r.

If the resistance of the load was increased slightly, the rate at which heat is being created within the seat of emf would ___.
remain constant
increase
decrease
be impossible to predict

23.  

A battery has an emf of 6.20 V and an internal resistance of 0.010. If the battery is connected to a resistor that draws a current of 20.0 A from the battery, what will be the potential difference across the terminals of the battery?
1.24 V
6.00 V
6.40 V
31.0 V

24.  

A battery has an emf of 6.20 V and an internal resistance of 0.010. If the battery is connected to a battery charger that causes a charging current of 20.0 A to flow through the battery, what will be the potential difference across the terminals of the battery?
1.24 V
6.00 V
6.40 V
31.0 V

25.  

What must be the reading in the ammeter A for the circuit section shown?
0 A
6.0 A
8.0 A
12 A

26.  

In the circuit at the right, four identical cells each with an emf of 2 V and negligible internal resistance are connected together in series and parallel as shown.

The magnitude of the net emf applied across the load resistance is ___ V.
2
3
4
6
8

27.  

In the circuit at the right, four identical cells each with an emf of 2 V and negligible internal resistance are connected together in series and parallel as shown.

The current through cell 3 is ___ the current through cell 1.
less than
more than
equal to
incomparable with

28.  

In the circuit at the right, four identical cells each with an emf of 2 V and negligible internal resistance are connected together in series and parallel as shown.

If cell 1 was turned around in the circuit, the rate at which heat is being created within the load resistance would ___.
increase
decrease
remain constant
be unpredictable

29.  

In the circuit at the right, E1 > E2, r1 = r2 and R1 < R2.

If the resistance of the resistor R1 was decreased slightly, the reading of the ammeter would ___.
decrease
increase
remain constant
be impossible to predict

30.  

In the circuit at the right, E1 > E2, r1 = r2 and R1 < R2.

If the resistance R1 was increased slightly, the potential difference across the resistance R2 would ___.
increase
decrease
remain constant
be impossible to predict

31.  

In the circuit at the right, E1 > E2, r1 = r2 and R1 < R2.

If the resistance R1 was decreased slightly, the difference in potential across the terminals of the first source of emf, i.e., VT1, would ___.
increase
decrease
remain constant
be impossible to predict

32.  

In the circuit at the right, E1 > E2, r1 = r2 and R1 < R2.

If E2 was decreased slightly, the difference in potential across the terminals of the first source of emf, i.e., VT1, would ___.
increase
decrease
remain constant
be impossible to predict

33.  

In the circuit at the right, E1 > E2, r1 = r2 and R1 < R2.

If the resistance R1 was decreased slightly, E1 would ___.
increase
decrease
remain constant
be impossible to predict


Bosworth et al, ARCO MCAT SuperCourse (MacMillan, 1997). Copyright 1997, 1996, 1994, 1991 by Stefan Bosworth, Ronald Drucker, Edgar Schnebel, Denise Garlan, Rosie Soy and Marion Brisk. Used by permission of MacMillan, Inc.

For more information, go to http://www.novapress.net/mcat/books.html.

The Virtual Prof's Physics Study Guide for the MCAT. Copyright 1997 by Glen Terrell and RonJon Publishing, Inc. Used by permission of Glen Terrell. For more information, go to http://www.virtualprof.com.


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