STRAIGHTERLINE INTRODUCTION TO
PHYSICS PHY250L LAB WORKSHEETS 2026
QUESTIONS WITH SOLUTIONS GRADED A+
⩥ Capacitors are widely used in electronic circuits where it is important
to store charge and/or energy or to trigger a timed electrical event. For
example, circuits with capacitors are designed to do such diverse things
as setting the flashing rate of Christmas lights, selecting what station a
radio picks up, and storing the electrical energy needed to fire an
electronic flash unit. Any pair of conductors that can be charged
electrically so that one conductor has excess positive charge and the
other conductor has an equal amount of excess negative charge on it is
called a capacitor. Answer: A capacitor can be made up of 2 differently
shaped blobs of metal or it can have any number of regular symmetric
shapes, such as one hollow metal sphere inside another, or a metal rod
inside a hollow metal cylinder (figure 8-1, page 150).
⩥ The type of capacitor that is the easiest to analyze is the parallel plate
capacitor. We will focus exclusively on these.. Answer: Although many
of the most interesting properties of capacitors come in the operation of
AC (alternating current) circuits (where current is first moves in one
direction and then in the other), we will limit our present study to the
behavior of capacitors in DC (direct current) circuits.
The circuit symbol for a capacitor is a simple pair of lines as shown in
Figure 1-2. Note that it is similar to the symbol for a battery, except that
both parallel lines are the same length for the capacitor.
,⩥ symbol for capacitor in a circuit. Answer:
⩥ Investigation 1: Capacitance, Area, and Separation. Answer: The usual
method for transferring equal and opposite charges to the plates of a
capacitor is to use a battery or power supply to produce a potential
difference between the two conductors. Electrons will then flow from
one conductor (leaving a net positive charge) and to the other (making
its net charge negative) until the potential difference produced between
the two conductors is equal to that of the battery (see figure 8-3, page
151)
⩥ In general, the amount of charge needed to produce a potential
difference equal to that of the battery will depend on the size, shape,
location of the conductors relative to each other, and the properties of
the material between the conductors. The capacitance, or the ability to
store electric charge, of a given capacitor is defined as the ratio of the
magnitude of the charge, q (on either one of the conductors) to the
voltage (potential difference), V, applied across the two conductors.
Thus. Answer: C = q/V
⩥ Capacitance is defined as. Answer: a measure of the amount of net or
excess charge on either one of the conductors per unit potential
difference. Thus the more charge a capacitor can store at a given voltage,
the larger the capacitance.
,-d = spacing
-A = area
-V = voltage
⩥ For a fixed voltage from a battery, the net charge found on either plate
is proportional to the capacitance of the pair of conductors and the
applied voltage. Answer: q = CV
⩥ Activity 1-1: Predicting the dependence pf capacitance on area and
separation. Answer: Consider two identical metal plates of area A that
are separated by a distance d. The space between the plates is filled with
a non- conducting material (air, for instance). Suppose each plate is
connected to one of the terminals of a battery.
⩥ question 1-1: What type of excess charge will build up on the metal
plate that is attached to the negative terminal of the battery? What type
of excess charge will build up on the plate that is connected to the
positive terminal of the battery? Explain.. Answer: -negative charges on
the negative terminal
-positive charges on the positive terminal
⩥ question 1-2: Can the excess positive charges on one plate of a
charged parallel plate capacitor exert forces on the excess negative
charges on the other plate? Explain. Answer: Yes, electric field can pass
through non-conducting material
, ⩥ question 1-3: Consider two identical metal plates of area A that are
separated by a distance d shown in figure 8-3 (page 151). If the area, A,
of the plates were increased (with the spacing and potential difference
between the plates held constant) what do you think would happen to the
amount of excess charge on each of the plates? Explain your reasoning.
How will this affect the capacitance of the capacitor? [Hint: Do the
electric field and potential difference between the plates depend on the
total charge one each plate, or on the charge permit area?]. Answer:
excess charge should decrease as well as capacitance too because
capacitance and area are directly proportional
⩥ question 1-4: If the battery is then disconnected, what do you think
would happen to the potential difference between the plates if the
separation, d, were decreased with the excess charge on each plate held
constant? Explain. [Hint: What happens to the electric field between the
plates as d decreases while the excess charge is kept constant by
disconnecting the capacitor form the battery? What happens to the
potential difference across the plates as d is made smaller after the
capacitor is disconnected from the battery?]. Answer: -potential
difference will decrease
Q = AεV/d
⩥ The unit of capacitance is the farad, F, named after Michael Faraday.
One farad is equal to one coulomb/volt. As you should be able to
demonstrate to yourself shortly, the farad is a very large capacitance.
Thus, actual capacitances are often expressed in smaller units with
PHYSICS PHY250L LAB WORKSHEETS 2026
QUESTIONS WITH SOLUTIONS GRADED A+
⩥ Capacitors are widely used in electronic circuits where it is important
to store charge and/or energy or to trigger a timed electrical event. For
example, circuits with capacitors are designed to do such diverse things
as setting the flashing rate of Christmas lights, selecting what station a
radio picks up, and storing the electrical energy needed to fire an
electronic flash unit. Any pair of conductors that can be charged
electrically so that one conductor has excess positive charge and the
other conductor has an equal amount of excess negative charge on it is
called a capacitor. Answer: A capacitor can be made up of 2 differently
shaped blobs of metal or it can have any number of regular symmetric
shapes, such as one hollow metal sphere inside another, or a metal rod
inside a hollow metal cylinder (figure 8-1, page 150).
⩥ The type of capacitor that is the easiest to analyze is the parallel plate
capacitor. We will focus exclusively on these.. Answer: Although many
of the most interesting properties of capacitors come in the operation of
AC (alternating current) circuits (where current is first moves in one
direction and then in the other), we will limit our present study to the
behavior of capacitors in DC (direct current) circuits.
The circuit symbol for a capacitor is a simple pair of lines as shown in
Figure 1-2. Note that it is similar to the symbol for a battery, except that
both parallel lines are the same length for the capacitor.
,⩥ symbol for capacitor in a circuit. Answer:
⩥ Investigation 1: Capacitance, Area, and Separation. Answer: The usual
method for transferring equal and opposite charges to the plates of a
capacitor is to use a battery or power supply to produce a potential
difference between the two conductors. Electrons will then flow from
one conductor (leaving a net positive charge) and to the other (making
its net charge negative) until the potential difference produced between
the two conductors is equal to that of the battery (see figure 8-3, page
151)
⩥ In general, the amount of charge needed to produce a potential
difference equal to that of the battery will depend on the size, shape,
location of the conductors relative to each other, and the properties of
the material between the conductors. The capacitance, or the ability to
store electric charge, of a given capacitor is defined as the ratio of the
magnitude of the charge, q (on either one of the conductors) to the
voltage (potential difference), V, applied across the two conductors.
Thus. Answer: C = q/V
⩥ Capacitance is defined as. Answer: a measure of the amount of net or
excess charge on either one of the conductors per unit potential
difference. Thus the more charge a capacitor can store at a given voltage,
the larger the capacitance.
,-d = spacing
-A = area
-V = voltage
⩥ For a fixed voltage from a battery, the net charge found on either plate
is proportional to the capacitance of the pair of conductors and the
applied voltage. Answer: q = CV
⩥ Activity 1-1: Predicting the dependence pf capacitance on area and
separation. Answer: Consider two identical metal plates of area A that
are separated by a distance d. The space between the plates is filled with
a non- conducting material (air, for instance). Suppose each plate is
connected to one of the terminals of a battery.
⩥ question 1-1: What type of excess charge will build up on the metal
plate that is attached to the negative terminal of the battery? What type
of excess charge will build up on the plate that is connected to the
positive terminal of the battery? Explain.. Answer: -negative charges on
the negative terminal
-positive charges on the positive terminal
⩥ question 1-2: Can the excess positive charges on one plate of a
charged parallel plate capacitor exert forces on the excess negative
charges on the other plate? Explain. Answer: Yes, electric field can pass
through non-conducting material
, ⩥ question 1-3: Consider two identical metal plates of area A that are
separated by a distance d shown in figure 8-3 (page 151). If the area, A,
of the plates were increased (with the spacing and potential difference
between the plates held constant) what do you think would happen to the
amount of excess charge on each of the plates? Explain your reasoning.
How will this affect the capacitance of the capacitor? [Hint: Do the
electric field and potential difference between the plates depend on the
total charge one each plate, or on the charge permit area?]. Answer:
excess charge should decrease as well as capacitance too because
capacitance and area are directly proportional
⩥ question 1-4: If the battery is then disconnected, what do you think
would happen to the potential difference between the plates if the
separation, d, were decreased with the excess charge on each plate held
constant? Explain. [Hint: What happens to the electric field between the
plates as d decreases while the excess charge is kept constant by
disconnecting the capacitor form the battery? What happens to the
potential difference across the plates as d is made smaller after the
capacitor is disconnected from the battery?]. Answer: -potential
difference will decrease
Q = AεV/d
⩥ The unit of capacitance is the farad, F, named after Michael Faraday.
One farad is equal to one coulomb/volt. As you should be able to
demonstrate to yourself shortly, the farad is a very large capacitance.
Thus, actual capacitances are often expressed in smaller units with
