BASIC CONCEPTS

The following 75 questions concern basic units, definitions, laws, and relations between important circuit quantities. In this version of the exam, the first choice is always the correct one. In the actual exam, the correct choice could be in any position, and there may be other changes to the choices. You can always assume that numerical values for the resistance of resistors, inductance of inductors and capacitance of capacitors are positive.



1. Charge is measured in
  1. coulombs
  2. volts
  3. amperes
  4. watts
  5. joules


2. Current is measured in
  1. amperes
  2. volts
  3. coulombs
  4. watts
  5. joules


3. Power is measured in
  1. watts
  2. volts
  3. coulombs
  4. amperes
  5. joules


4. Energy is measured in
  1. joules
  2. volts
  3. coulombs
  4. amperes
  5. watts


5. Resistance is measured in
  1. ohms
  2. henrys
  3. farads
  4. watts
  5. joules


6. Inductance is measured in
  1. henrys
  2. ohms
  3. farads
  4. watts
  5. joules


7. Capacitance is measured in
  1. farads
  2. henrys
  3. ohms
  4. watts
  5. joules


8. The current i through a capacitor and the charge q that it holds are related by
  1. i = dq/dt
  2. q = di/dt
  3. q = 0.5 i2
  4. i = 0.5 q2
  5. q i = 1


9. The magnetic flux linkage l in an inductor and the voltage v across its terminals are related by
  1. v = dl/dt
  2. l = dv/dt
  3. v = 0.5 l2
  4. l = 0.5 v2
  5. v l = 1


10. Kirchhoff's Voltage Law (KVL) can be stated as
  1. The sum of the voltage drops around any closed path is zero
  2. The sum of the voltages at all the nodes is zero
  3. The sum of the voltages across all the elements equals the sum of the currents through all the elements
  4. The voltage across an element is proportional to the current through the element
  5. The sum of the voltages into a node is equal to the sum of the voltages out of the node


11. Kirchhoff's Voltage Law (KVL) can be stated as
  1. The voltage rise from Node a to Node b is the same for every path from a to b
  2. The voltage rise from Node a to Node b is zero if Node b is a ground node
  3. The total voltage into a node equals the total voltage out of a node
  4. The voltage at Node a with Node b grounded is the same as the voltage at Node b with Node a grounded
  5. The voltage between any two nodes is independent of the total current flowing in the network


12. Kirchhoff's Current Law (KCL) can be stated as
  1. The sum of the currents flowing into any node is zero
  2. The sum of the currents flowing around any closed loop is zero
  3. The sum of the currents through all elements equals the sum of the voltages across the elements
  4. The current through an element is proportional to the voltage across the element
  5. The sum of the currents flowing clockwise around any mesh is equal to the sum of the currents flowing counterclockwise around the same mesh


13. Kirchhoff's Current Law (KCL) can be stated as
  1. The sum of the currents entering a node equals the sum of the currents leaving the node
  2. The sum of the currents entering a node equals the sum of the currents entering the ground node
  3. The current flowing around any mesh is independent of the voltage sources in that mesh
  4. The sum of the currents flowing around a mesh is zero
  5. The sum of the currents flowing through any element is equal to the voltage dropped across that element


14. When two or more circuit elements are connected in series
  1. the currents flowing through them are the same
  2. the voltages across them are the same
  3. the powers dissipated in them are the same
  4. the energies stored in them are the same
  5. the flux linkages produced by them are the same


15. When two or more circuit elements are connected in parallel
  1. the voltages across them are the same
  2. the currents flowing through them are the same
  3. the powers dissipated in them are the same
  4. the energies stored in them are the same
  5. the flux linkages produced by them are the same


16. The voltage v(t) across an independent voltage source
  1. does not depend on the current i(t) through the source
  2. is proportional to the current i(t) through the source
  3. does not depend on time t
  4. cannot provide power to an external circuit
  5. always provides power to an external circuit



17. The current i(t) through an independent current source
  1. does not depend on the voltage v(t) across the source
  2. is proportional to the voltage v(t) across the source
  3. does not depend on time t
  4. cannot provide power to an external circuit
  5. always provides power to an external circuit



18. The voltage vc for the dependent source shown
  1. is proportional to the voltage vx somewhere else in the circuit
  2. is proportional to the current i through the source
  3. cannot provide power to an external circuit
  4. always provides power to an external circuit
  5. is never negative



19. The voltage vc for the dependent source shown
  1. is proportional to the current ix somewhere else in the circuit
  2. is proportional to the current i through the source
  3. cannot provide power to an external circuit
  4. always provides power to an external circuit
  5. is never negative



20. The current ic for the dependent source shown
  1. is proportional to the current ix somewhere else in the circuit
  2. is proportional to the voltage v across the source
  3. cannot provide power to an external circuit
  4. always provides power to an external circuit
  5. is never negative



21. The current ic for the dependent source shown
  1. is proportional to the voltage vx somewhere else in the circuit
  2. is proportional to the voltage v across the source
  3. cannot provide power to an external circuit
  4. always provides power to an external circuit
  5. is never negative



22. The open-loop voltage gain of an ideal operational amplifier is
  1. infinite
  2. unity
  3. zero
  4. inverting
  5. noninverting



23. The current flowing into either input of an ideal operational amplifier is
  1. zero
  2. unity
  3. infinite
  4. inverting
  5. noninverting



24. The current i0 flowing out of an ideal operational amplifier is
  1. found by writing a KCL equation at the output node
  2. equal to the sum of the currents i1 and i2
  3. zero, if the amplifier is ideal
  4. never negative
  5. determined by the largest resistor in the circuit



25. The circuit shown is called
  1. a voltage follower
  2. an inverting amplifier
  3. a full-wave rectifier
  4. an integrator
  5. a differentiator



26. The circuit shown is called
  1. a non-inverting amplifier
  2. an inverting amplifier
  3. a full-wave rectifier
  4. an integrator
  5. a differentiator



27. The circuit shown is called
  1. an inverting amplifier
  2. a non-inverting amplifier
  3. a full-wave rectifier
  4. an integrator
  5. a differentiator



28. Ohm's Law is
  1. v = R i
  2. v = L di/dt
  3. p = i2 R
  4. p = v i
  5. i = C dv/dt


29. The resistance R and the conductance G of a resistor are related by
  1. G = 1 / R
  2. G = 2 p R
  3. G = 2 p / R
  4. R + G = 1
  5. G = e-R


30. The voltage v across an inductor and the current i through it are related by
  1. v = L di/dt
  2. i = L dv/dt
  3. v = L i
  4. i = L v
  5. dv/dt = L i



31. The voltage v across a capacitor and the current i through it are related by
  1. i = C dv/dt
  2. v = C di/dt
  3. i = C v
  4. v = C i
  5. di/dt = C v



32. The relationship between power p and energy w is
  1. p = dw/dt
  2. w = dp/dt
  3. p = w2
  4. w = p2
  5. p = 1 / w


33. The instantaneous power p(t) flowing into a circuit element
  1. is given by p = v i
  2. is given by p = v / i
  3. is given by p = i / v
  4. can never be negative
  5. can never be positive



34. The energy w(t) transferred into a circuit element
  1. is given by
  2. is given by w = v i
  3. is given by w = v / i
  4. is given by w = i / v
  5. is zero if t is negative



35. The power dissipated by a resistor is
  1. p = i2 R
  2. p = v2 R
  3. p = v i R
  4. p = v i / R
  5. p = i2 / R



36. The power dissipated by a resistor is
  1. p = v2 / R
  2. p = v2 R
  3. p = v i R
  4. p = v i / R
  5. p = i2 / R



37. The power dissipated by a resistor
  1. cannot be negative
  2. is called the conductance
  3. is measured in joules
  4. is equal to the power that it generates
  5. is purely imaginary


38. The energy stored in an inductor L is given by
  1. 0.5 L i2
  2. L di/dt
  3. v i
  4. 0.5 L dv/dt
  5. 0.5 v2 / L



39. The energy stored in a capacitor C is
  1. 0.5 C v2
  2. C v
  3. C dv/dt
  4. 0.5 C di/dt
  5. 0.5 i2 / C



40. If a stable linear network is driven by a sinusoidal source, in steady state
  1. every voltage and every current has the same frequency
  2. every voltage and every current has the same amplitude
  3. every voltage and every current has the same phase
  4. all voltages and currents are constant
  5. the power absorbed by the resistive elements is equal to the power provided by the reactive elements


41. The angular frequency w (in rad/s) is related to the frequency f (in Hz) by
  1. w = 2 p f
  2. f = 2 p w
  3. w = 1 / f
  4. w = 2 p / f
  5. w + f = 1


42. If a voltage is given by v(t) = Vm cos(w t + f), the corresponding phasor voltage V is
  1. V = Vm ej f
  2. V = Vm ej w t
  3. V = Re{ Vm ej(w t + f) }
  4. V = 0.5(Vm + Vm *)
  5. V = j w Vm


43. If the phasor current for a frequency w is given by I = Im ej f , the corresponding time-domain current i(t) is
  1. i(t) = Im cos(w t + f)
  2. i(t) = Im ej(w t + f)
  3. i(t) = Im e- f t cos(w t)
  4. i(t) = Im e- w t cos(f t)
  5. i(t) = Im e- jw t cos(f t)


44. If a phasor voltage V is written in polar form as V = Vm ej f
  1. Vm is called the amplitude
  2. Vm is called the admittance
  3. f is called the frequency
  4. f is called the susceptance
  5. Vm is purely imaginary


45. If a phasor current I is written in polar form as I = Im ej f
  1. f is called the phase angle
  2. f is called the frequency
  3. Im is called the conductance
  4. Im is called the admittance
  5. Im is purely imaginary


46. The relationship between the phasor voltage V, the phasor current I and the impedance Z is
  1. V = Z I
  2. I = Z V
  3. Z = V I*
  4. Z = V + I
  5. Z = |V| |I| cos q


47. If I = Im ej f and Z = Zm ej q then the product Z I is given by
  1. Zm Im ej(q+f)
  2. Zm Im ej(q-f)
  3. Zm Im ej(qf)
  4. (Zm + Im) ej(q+f)
  5. (Zm + Im ) ej(qf)


48. The impedance Z and the admittance Y are related by
  1. Y = 1 / Z
  2. Y = 2 p Z
  3. Y = 2 p / Z
  4. Y + Z = 1
  5. Y = ej w Z


49. The impedance Z and the admittance Y are related by
  1. Y Z = 1
  2. Z = 2 p Y
  3. Z = 2 p / Y
  4. Z + Y = 1
  5. Z = ej w Y


50. If an impedance Z is written in rectangular form as Z = R +j X,
  1. X is called the reactance
  2. X cannot be positive
  3. X cannot be negative
  4. X must become infinite at high frequencies
  5. R and X are measured in different units


51. The impedance of an inductor L at angular frequency w is
  1. Z = j w L
  2. Z = 1 / j w L
  3. Z = 0.5 w 2
  4. Z = w L
  5. Z = 1 / w L


52. The impedance of an inductor is
  1. purely imaginary
  2. infinite at DC
  3. constant
  4. a sinusoidal function of frequency
  5. indeterminate


53. The reactance of an inductor L at angular frequency w is
  1. X = w L
  2. X = -w L
  3. X = 1 / w L
  4. X = - 1 / w L
  5. X = j w L


54. The reactance of an inductor
  1. is never negative
  2. is never positive
  3. decreases in magnitude as frequency increases
  4. decreases in magnitude as the inductance increases
  5. is equal to the energy stored in the inductor


55. The impedance of a capacitor C at angular frequency w is
  1. Z = 1 / j w C
  2. Z = j w C
  3. Z = 0.5 w2 C
  4. Z = w C
  5. Z = 1 / w C


56. The impedance of a capacitor is
  1. purely imaginary
  2. zero at DC
  3. constant
  4. a sinusoidal function of frequency
  5. indeterminate


57. The reactance of a capacitor C at angular frequency w is
  1. X = - 1 / w C
  2. X = 1 / w C
  3. X = -w C
  4. X = w C
  5. X = 1 / j w C


58. The reactance of a capacitor
  1. is never positive
  2. is never negative
  3. increases in magnitude as frequency increases
  4. increases as the capacitance increases
  5. is equal to the energy stored in the capacitor


59. The impedance of a resistor R at angular frequency w is
  1. Z = R
  2. Z = j R
  3. Z = j w R
  4. Z = 1 / R
  5. Z =1 / j w R


60. At very high frequencies, an inductor acts like
  1. an open circuit
  2. a short circuit
  3. a voltage source
  4. a capacitor
  5. an operational amplifier


61. At very low frequencies, an inductor acts like
  1. a short circuit
  2. an open circuit
  3. a current source
  4. a capacitor
  5. an operational amplifier


62. At very high frequencies, a capacitor acts like
  1. a short circuit
  2. an open circuit
  3. a current source
  4. an inductor
  5. an operational amplifier


63. At very low frequencies, a capacitor acts like
  1. an open circuit
  2. a short circuit
  3. a voltage source
  4. an inductor
  5. an operational amplifier


64. The equivalent impedance for three impedances connected in series is



65. The equivalent impedance for three impedances connected in parallel is



66. The circuit shown is called
  1. a voltage divider
  2. a current divider
  3. an inverting amplifier
  4. a non-inverting amplifier
  5. a full-wave rectifier



67. For the circuit shown



68. The circuit shown is called
  1. a current divider
  2. a voltage divider
  3. an inverting amplifier
  4. a non-inverting amplifier
  5. a full-wave rectifier



69. For the circuit shown,



70. An inactive or "dead" voltage source is equivalent to
  1. a short circuit
  2. an open circuit
  3. an ideal inductor
  4. an ideal capacitor
  5. an active or "live" current source


71. An inactive or "dead" current source is equivalent to
  1. an open circuit
  2. a short circuit
  3. an ideal inductor
  4. an ideal capacitor
  5. an active or "live" voltage source


72. The Thevenin equivalent impedance can be obtained by
  1. applying a test source with all independent sources dead
  2. applying a test source with all dependent sources dead
  3. short circuiting all inductors and open circuiting all capacitors
  4. open circuiting all inductors and short circuiting all capacitors
  5. replacing all inductors by capacitors and all capacitors by inductors


73. The Thevenin equivalent voltage can be obtained by
  1. solving for the open-circuit voltage
  2. solving for short-circuit voltage
  3. solving for the open-circuit current
  4. short circuiting all inductors and open circuiting all capacitors
  5. open circuiting all inductors and short circuiting all capacitors


74. The Norton equivalent current can be obtained by
  1. solving for the short-circuit current
  2. solving for the open-circuit current
  3. solving for the short-circuit voltage
  4. short circuiting all inductors and open circuiting all capacitors
  5. open circuiting all inductors and short circuiting all capacitors


75. The impedances in the Thevenin and Norton equivalent circuits
  1. are equal
  2. are complex conjugates of one another
  3. are negatives of one another
  4. are undefined when w is zero
  5. are undefined when w is infinite


End of Questions on Basic Concepts