You can only unlock the chapter using a special code that we will send you via the Viber app. Receiving a message is free of charge and with no obligations.
My phone number:
Get a code
In compliance with the law, persons under the age of 15 can enter their phone number only in the presence of a parent or guardian.
4-character code:
Check the received code
The page will be refreshed automatically in a few seconds.
To ensure the proper functioning of the website, OpenProf uses cookies that do not store personal data. By continuing to use the website, you agree to cookies. Tell me more »
and then connected in series with a switch, a resistor of resistance 
and a sensitive ammeter, as shown in the figure below.
. It is then discharged through a resistor R. The circuit is shown in the figure below.
of the potential difference 
across the resistor 
during the discharge of the capacitor is shown in the graph above.
of the discharge of the capacitor, 
of energy is transferred to the resistor 
.
when the potential difference across the capacitor changes from 
to 
.
, is insulated from its surroundings. The sphere has charge 
. This charge is on the surface of the sphere but it may be considered to be a point charge at its centre, as illustrated in the figure below.
of the sphere is given by the expression
. Determine the capacitance of the sphere.
to 
. Calculate the energy dissipated in the spark.
is charged to a potential difference of 
. It is then partially discharged through a resistor. The potential difference is reduced to 
. Calculate the energy dissipated in the resistor during the discharge.
carries a charge 
. The charge may be assumed to be concentrated at the centre of the sphere.
of the sphere is given by
and carries a charge of 
. Calculate
. The variation with 
on one plate is shown in the graph below.
to 
.
across its terminals is 
. The capacitor is connected into the circuit shown below.
on the plates of capacitor C as the capacitor discharges.
.
apart, as shown in the figure below. The capacitance 
is inversely proportional to 
between the plates.
on one of the plates and for the energy 
stored in the capacitor.
. They are then moved closer together by a distance 
, as shown in the figure below.
is situated in a vacuum. The charge 
on the sphere may be considered to be a point charge at the centre of the sphere. Define capacitance and hence show that the capacitance 
of the sphere is given by the expression
.
. A spark occurs, partially discharging the sphere so that its potential is reduced to 
. Determine the energy of the spark.
is charged using a battery of e.m.f. 
, as shown in the figure below.
is closed and switch 
is open.
by closing 
. Suggest why this value is different from your answer in (a).
and negligible internal resistance. The capacitance of the capacitor is 
. The switch is closed at time 
. During the time interval 
, the charge passing through the resistor is 
.
across the capacitor,
and is charged to a potential of 
. Calculate the charge, in coulomb, on the sphere.
. Calculate
. The capacitor is then connected across a resistor for a short time. It is then disconnected. The energy stored in the capacitor is reduced to 
of its initial value. Determine, in terms of 
and 
are connected in series with a battery of electromotive force (e.m.f.) 
, as shown in the figure below.
, a resistor 
, and a two-way switch are connected in the circuit shown in the figure below.
after the switch is moved the charge on the capacitor is 
. The variation with 
(Q/
) is shown in the graph below.
.
.
and 
, and a resistor of resistance 
, are connected into the circuit shown below.
.
.
of the charge 
on one of the plates of a capacitor is shown in the graph below.
power supply and two resistors R and S as shown in the figure below.
and the resistance of S is 
. The switch can be in either position X or position Y. The switch is in position X so that the capacitor is fully charged. Calculate the energy 
stored in the capacitor.
and capacitor B has capacitance 
. The electromotive force (e.m.f.) of the cell is 
. The two-way switch S is initially at position X, and capacitor B is initially uncharged.
stored in capacitor A.
across capacitor B is given by
in the total energy that is stored in the capacitors as a result of the change of the position of the switch.
is connected across the output terminals of a bridge rectifier, as shown in the figure below.
of the potential difference 
across the resistor 
is shown in the graph below.
to time 
.
