Download up11_educue_ch31 - University of Manchester

Q31.1
A resistor is connected across an ac source
as shown. Which graph correctly shows the
instantaneous current through the resistor
and the instantaneous voltage vab across the
resistor?
(current in purple, voltage in blue)
1.
2.
3.
A31.1
A resistor is connected across an ac source
as shown. Which graph correctly shows the
instantaneous current through the resistor
and the instantaneous voltage vab across the
resistor?
(current in purple, voltage in blue)
1.
2.
3.
Q31.2
An inductor is connected across an ac source
as shown. Which graph correctly shows the
instantaneous current through the inductor
and the instantaneous voltage vab across the
inductor?
(current in purple, voltage in blue)
1.
2.
3.
A31.2
An inductor is connected across an ac source
as shown. Which graph correctly shows the
instantaneous current through the inductor
and the instantaneous voltage vab across the
inductor?
(current in purple, voltage in blue)
1.
2.
3.
Q31.3
A capacitor is connected across an ac source
as shown. Which graph correctly shows the
instantaneous current through the capacitor
and the instantaneous voltage vab across the
capacitor?
(current in purple, voltage in blue)
1.
2.
3.
A31.3
A capacitor is connected across an ac source
as shown. Which graph correctly shows the
instantaneous current through the capacitor
and the instantaneous voltage vab across the
capacitor?
(current in purple, voltage in blue)
1.
2.
3.
Q31.4
An L-R-C series circuit as shown is
operating at its resonant frequency. At this
frequency, how are the values of the
capacitive reactance XC, the inductive
reactance XL, and the resistance R related to
each other?
1. XL = R; XC can have any value
2. XC = R; XL can have any value
3. XC = XL; R can have any value
4. XC = XL = R
5. none of the above
A31.4
An L-R-C series circuit as shown is
operating at its resonant frequency. At this
frequency, how are the values of the
capacitive reactance XC, the inductive
reactance XL, and the resistance R related to
each other?
1. XL = R; XC can have any value
2. XC = R; XL can have any value
3. XC = XL; R can have any value
4. XC = XL = R
5. none of the above
Q31.5
In an L-R-C series circuit as shown, the
current has a very small amplitude if the
emf oscillates at a very high frequency.
Which circuit element causes this behavior?
1. the resistor R
2. the inductor L
3. the capacitor C
4. misleading question — the current actually has a very
large amplitude if the frequency is very high
A31.5
In an L-R-C series circuit as shown, the
current has a very small amplitude if the
emf oscillates at a very high frequency.
Which circuit element causes this behavior?
1. the resistor R
2. the inductor L
3. the capacitor C
4. misleading question — the current actually has a very
large amplitude if the frequency is very high
Q31.6
In an L-R-C series circuit as shown, there is
a phase angle between the instantaneous
current through the circuit and the
instantaneous voltage vad across the entire
circuit. For what value of the phase angle is
the greatest power delivered to the resistor?
1. zero
2. 90°
3. 180°
4. 270°
5. none of the above
A31.6
In an L-R-C series circuit as shown, there is
a phase angle between the instantaneous
current through the circuit and the
instantaneous voltage vad across the entire
circuit. For what value of the phase angle is
the greatest power delivered to the resistor?
1. zero
2. 90°
3. 180°
4. 270°
5. none of the above
Q31.7
In the transformer
shown in the drawing,
there are more turns in
the secondary than in
the primary. In this
situation,
1. the current amplitude is greater in the primary than in
the secondary
2. the current amplitude is smaller in the primary than in
the secondary
3. the current amplitude is the same in the primary and in
the secondary
4. not enough information given to decide
A31.7
In the transformer
shown in the drawing,
there are more turns in
the secondary than in
the primary. In this
situation,
1. the current amplitude is greater in the primary than in
the secondary
2. the current amplitude is smaller in the primary than in
the secondary
3. the current amplitude is the same in the primary and in
the secondary
4. not enough information given to decide