Question 1

The circuit shown was wired for the purpose of measuring the resistance of the lamp L. Inspection shows that:

Accepted Answer

A)  voltmeter V and rheostat R should be interchanged 
B)  the circuit is satisfactory 
C)  the ammeter A should be in parallel with R, not L 
D)  the meters, V and A, should be interchanged 
E)  L and V should be interchanged 
A)  voltmeter V and rheostat R should be interchanged 
B)  the circuit is satisfactory 
C)  the ammeter A should be in parallel with R, not L 
D)  the meters, V and A, should be interchanged 
E)  L and V should be interchanged

Question 2

Resistor 1 has twice the resistance of resistor 2. They are connected in parallel to a battery. The ratio of the thermal energy dissipation by 1 to that by 2 is:

Accepted Answer

A)  1:4 
B)  1:2 
C)  1:1 
D)  2:1 
E)  4:1 
A)  1:4 
B)  1:2 
C)  1:1 
D)  2:1 
E)  4:1

Question 3

When switch S is open, the ammeter in the circuit shown reads 2.0 A. When S is closed, the ammeter reading:

Accepted Answer

A)  increases slightly 
B)  remains the same 
C)  decreases slightly 
D)  doubles 
E)  halves 
A)  increases slightly 
B)  remains the same 
C)  decreases slightly 
D)  doubles 
E)  halves

Question 4

A galvanometer has an internal resistance of 12  $\Omega$ and requires 0.01 A for full scale deflection. To convert it to a voltmeter reading 3 V full scale, one must use a series resistance of:

Accepted Answer

A)  102  $\Omega$ 
B)  288  $\Omega$ 
C)  300  $\Omega$ 
D)  360  $\Omega$ 
E)  412  $\Omega$ 
A)  102  $\Omega$ 
B)  288  $\Omega$ 
C)  300  $\Omega$ 
D)  360  $\Omega$ 
E)  412  $\Omega$

Question 5

Resistor 1 has twice the resistance of resistor 2. The two are connected in parallel and a potential difference is maintained across the combination. The rate of thermal energy dissipation in 1 is:

Accepted Answer

A)  the same as that in 2 
B)  twice that in 2 
C)  half that in 2 
D)  four times that in 2 
E)  one fourth that in 2 
A)  the same as that in 2 
B)  twice that in 2 
C)  half that in 2 
D)  four times that in 2 
E)  one fourth that in 2

Question 6

In the circuit shown, both resistors have the same value R. Suppose switch S is initially closed. When it is then opened, the circuit has a time constant  $ \tau $a Conversely, suppose S is initially open. When it is then closed, the circuit has a time constant  $ \tau $b The ratio  $ \tau $a/ $ \tau $b is:

Accepted Answer

A)  1 
B)  2 
C)  0.5 
D)  0.667 
E)  1.5 
A)  1 
B)  2 
C)  0.5 
D)  0.667 
E)  1.5

Question 7

Two wires made of the same material have the same length but different diameter. They are connected in parallel to a battery. The quantity that is NOT the same for the wires is:

Accepted Answer

A)  the end-to-end potential difference 
B)  the current 
C)  the current density 
D)  the electric field 
E)  the electron drift velocity 
A)  the end-to-end potential difference 
B)  the current 
C)  the current density 
D)  the electric field 
E)  the electron drift velocity

Question 8

Four circuits have the form shown in the diagram. The capacitor is initially uncharged and the switch S is open.   The values of the emf $\varepsilon$, resistance and R, and capacitance C for each for the circuits are   Rank the circuits according to the current just after switch S is closed least to greatest.

Accepted Answer

A)  1, 2, 3, 4 
B)  4, 3, 2, 1 
C)  4, 2, 3, 1 
D)  4, 2, 1, 3 
E)  3, 1, 2, 4 
A)  1, 2, 3, 4 
B)  4, 3, 2, 1 
C)  4, 2, 3, 1 
D)  4, 2, 1, 3 
E)  3, 1, 2, 4

Question 9

In the capacitor discharge formula q = q0e-t/RC the symbol t represents:

Accepted Answer

A)  the time constant 
B)  the time it takes for C to lose the fraction 1/e of its initial charge 
C)  the time it takes for C to lose the fraction (1 - 1/e) of its initial charge 
D)  the time it takes for C to lose essentially all of its initial charge 
E)  none of the above 
A)  the time constant 
B)  the time it takes for C to lose the fraction 1/e of its initial charge 
C)  the time it takes for C to lose the fraction (1 - 1/e) of its initial charge 
D)  the time it takes for C to lose essentially all of its initial charge 
E)  none of the above

Question 10

The positive terminals of two batteries with emf's of ε1 and ε2, respectively, are connected together. Here ε1 > ε2. The circuit is completed by connecting the negative terminals. If each battery has an internal resistance of r, the rate in watts at which electrical energy is converted to chemical energy in the smaller battery is:

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 11

Two 110-V light bulbs, one "25 W" and the other "100 W", are connected in series to a 110 V source. Then:

Accepted Answer

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 
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

Question 12

Two identical batteries, each with an emf of 18 V and an internal resistance of 1  $\Omega$, are wired in parallel by connecting their positive terminals together and connecting their negative terminals together. The combination is then wired across a 4- $\Omega$ resistor. The potential difference across the 4- $\Omega$ resistor is:

Accepted Answer

A)  4.0 V 
B)  8.0 V 
C)  14 V 
D)  16 V 
E)  29 V 
A)  4.0 V 
B)  8.0 V 
C)  14 V 
D)  16 V 
E)  29 V

Question 13

Two wires made of the same material have the same length but different diameters. They are connected in series to a battery. The quantity that is the same for the wires is:

Accepted Answer

A)  the end-to-end potential difference 
B)  the current 
C)  the current density 
D)  the electric field 
E)  the electron drift velocity 
A)  the end-to-end potential difference 
B)  the current 
C)  the current density 
D)  the electric field 
E)  the electron drift velocity

Question 14

"The sum of the emf's and potential differences around a closed loop equals zero" is a consequence of:

Accepted Answer

A)  Newton's third law 
B)  Ohm's law 
C)  Newton's second law 
D)  conservation of energy 
E)  conservation of charge 
A)  Newton's third law 
B)  Ohm's law 
C)  Newton's second law 
D)  conservation of energy 
E)  conservation of charge

Question 15

In the diagrams, all light bulbs are identical and all emf devices are identical. In which circuit (I, II, III, IV, V) will the bulbs glow with the same brightness as in circuit X?

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  IV 
E)  V 
A)  I 
B)  II 
C)  III 
D)  IV 
E)  V

Question 16

Suppose the current charging a capacitor is kept constant. Which graph below correctly gives the potential difference V across the capacitor as a function of time?

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  IV 
E)  V 
A)  I 
B)  II 
C)  III 
D)  IV 
E)  V

Question 17

Nine identical wires, each of diameter d and length L, are connected in series. The combination has the same resistance as a single similar wire of length L but whose diameter is:

Accepted Answer

A)  3d 
B)  9d 
C)  d/3 
D)  d/9 
E)  d/81 
A)  3d 
B)  9d 
C)  d/3 
D)  d/9 
E)  d/81

Question 18

A certain voltmeter has an internal resistance of 10,000  $\Omega$ and a range from 0 to 12 V. To extend its range to 120 V, use a series resistance of:

Accepted Answer

A)  1,111  $\Omega$ 
B)  90,000  $\Omega$ 
C)  100,000  $\Omega$ 
D)  108,000  $\Omega$ 
E)  120,000  $\Omega$ 
A)  1,111  $\Omega$ 
B)  90,000  $\Omega$ 
C)  100,000  $\Omega$ 
D)  108,000  $\Omega$ 
E)  120,000  $\Omega$

Question 19

A portion of a circuit is shown, with the values of the currents given for some branches. What is the direction and value of the current i?

Accepted Answer

A)  $\downarrow$, 6A 
B)  $\uparrow$, 6A 
C) $\downarrow$, 4A 
D) $\uparrow$, 4A 
E)  $\downarrow$, 2A 
A)  $\downarrow$, 6A 
B)  $\uparrow$, 6A 
C) $\downarrow$, 4A 
D) $\uparrow$, 4A 
E)  $\downarrow$, 2A

Question 20

The emf of a battery is equal to its terminal potential difference:

Accepted Answer

A)  under all conditions 
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)  under no conditions 
A)  under all conditions 
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)  under no conditions

Exam 27: Circuits

The circuit shown was wired for the purpose of measuring the resistance of the lamp L. Inspection shows that:

Resistor 1 has twice the resistance of resistor 2. They are connected in parallel to a battery. The ratio of the thermal energy dissipation by 1 to that by 2 is:

When switch S is open, the ammeter in the circuit shown reads 2.0 A. When S is closed, the ammeter reading:

A galvanometer has an internal resistance of 12 Ω\OmegaΩ and requires 0.01 A for full scale deflection. To convert it to a voltmeter reading 3 V full scale, one must use a series resistance of:

Resistor 1 has twice the resistance of resistor 2. The two are connected in parallel and a potential difference is maintained across the combination. The rate of thermal energy dissipation in 1 is:

Two wires made of the same material have the same length but different diameter. They are connected in parallel to a battery. The quantity that is NOT the same for the wires is:

In the capacitor discharge formula q = q0e-t/RC the symbol t represents:

Two 110-V light bulbs, one "25 W" and the other "100 W", are connected in series to a 110 V source. Then:

Two wires made of the same material have the same length but different diameters. They are connected in series to a battery. The quantity that is the same for the wires is:

"The sum of the emf's and potential differences around a closed loop equals zero" is a consequence of:

In the diagrams, all light bulbs are identical and all emf devices are identical. In which circuit (I, II, III, IV, V) will the bulbs glow with the same brightness as in circuit X?

Suppose the current charging a capacitor is kept constant. Which graph below correctly gives the potential difference V across the capacitor as a function of time?

Nine identical wires, each of diameter d and length L, are connected in series. The combination has the same resistance as a single similar wire of length L but whose diameter is:

A certain voltmeter has an internal resistance of 10,000 Ω\OmegaΩ and a range from 0 to 12 V. To extend its range to 120 V, use a series resistance of:

A portion of a circuit is shown, with the values of the currents given for some branches. What is the direction and value of the current i?

The emf of a battery is equal to its terminal potential difference:

Measurement

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Filters

A galvanometer has an internal resistance of 12 $\Omega$ and requires 0.01 A for full scale deflection. To convert it to a voltmeter reading 3 V full scale, one must use a series resistance of:

In the capacitor discharge formula q = q₀e^-^t^/^RC the symbol t represents:

A certain voltmeter has an internal resistance of 10,000 $\Omega$ and a range from 0 to 12 V. To extend its range to 120 V, use a series resistance of: