The diagram below shows a circuit conn/yii,3me h:wc9.d; fthz5 l zvected to a 12 V battery with negligible internal em/z dcihli;3z :9wty,v h5f.resistance.


What is the value of the current $I$ through the $2Ω$ resistor?

  A circuit is connectedm;ov8qv)o )yh2 8n6pac: ilbsggrxs u 7-66in across a $12\,V$ battery which provides $60\,J$ of electrical energy per second.
What is the rate of charge flow across the conductor?

  The following graph shows the relationship between current and potential difference across an unknown component in a series circuit.


Which of the following is true about the component?

  An electron accelerad r r3(4fgl-eqh ,tge6tes through a potential difference of $7\,kV$. How much work is done on the electron by the field?

  An electric circuit is connected ashd2sd xld( hs79p:)ks shown. An electric current of $2\,A$ flows through the electric cell with an internal resistance $r$


What is the value for $r $?

  A wire carries electrib/ol8 pxcfnp * mu06p(cal current. If $9.0×10^{12}$ electrons pass a given point in the wire every 4.5 seconds, what is the current in the wire?

  The variation of terminal potential differex:16 ; gqqq2w n, hvps5sev:ksnce$V$ across an electric cell with current $I$ coming out of the cell is shown in the graph.


What are the values of the emf $ϵ$ and internal resistance $r$ of the electric cell used in this circuit?

  A light dependent resistor (LDR) a(hpeymwp/)) cufl n9-ou6+mand a $10\,kΩ$ resistor are connected in series to a $12\,V$ D.C supply as shown.


When the LDR is in the dark it has a resistance of $20\,kΩ $. Which of the following gives the potential difference $V$ across the light dependent resistor under these conditions?

  Consider the circuits below that are located side by side as shown. One of these circuits includes a thermistor, which decreases in resistance as it increases in temperature.


Lamp brightness；Reason

  If the radius of a segment of wire is doubled, and its length decreases by half, by what factor does the wire's resistance change?

  A student constructed the series circuit below.


After closing the switch, which of the following is true about how the temperature of component A and current in the circuit will change with time?
Temperature of ACurrent in the circuit

  A cell is connected to a variable resistor. The terminal potential difference (p.d.) and current through the cell are measured and plotted on the graph shown. What is the internal resistance of the cell?

  A cell with internal resistance r and emf ϵ is connected to a variable resistor R, an ideal ammeter and an ideal voltmeter.


1.State what is meant by terminal voltage.
2.Explain why the reading of the voltmeter is less than ϵ.
The variation of the reading of the voltmeter with the current I is shown in the graph.

3.Determine the emf ϵ and the internal resistance r of the cell.ϵ=   ≪V≫
r=   ≪Ω≫

  Electrons are accelerated between two conducting plates that have a potential dija6w,:dsv 63(tvpys+cbrp )b fference of bw vb+d3rty js cp(a66:,) spv100V. Estimate the total energy that would be delivered to $10^{21}$ electrons by the conducting plates.

  A circuit of a cell of electromotive force (emf)+ ogcb,watk )(9+ p8hu, ihahdcko33e $18.0\,VE and negligible internal resistance connected to three resistors of resistance $6.0\,Ω$


The ammeter is ideal. What is the reading of the ammeter?

  Two identical lamps h ul3v( rv:qs.. 9twul$L_1​$ and $L_2​$ are connected to a cell with no internal resistance as shown below. Resistors $R_1​$ and $R_2​$ are also identical. Switch $S$ controls part of the circuit.


Which of the following statements about the brightness of the lamp $L_2​$ are correct?

I. If the resistance of $R_2$​ increases, the brightness of $L_2​$ increases.
II. If the resistance of $R_1​$ increases, the brightness of $L_2​$​ decreases.
III. If switch $S$ is opened, the brightness of $L_2​$ ​ does not change.

  A light bulb is lit by f7a)d3o9tt xi:8 joklgk x m;/$1\,kJ$ of energy being transferred to the bulb by a potential difference of $200\,V$. This transfer happens over a time of 2 seconds.
What is the current passing through the bulb?

  A cell with emf $ϵ$ and internal resistance $r$ is connected to a variable resistor $R$, an ammeter and a voltmeter as shown.


Both meters are ideal, and the variable resistor can vary from 0 to $9Ω$.
1.Derive a relation for the power $P$ dissipated in the variable resistor in terms of the internal resistance $r$, emf $ϵ$ and the value of the variable resistor $R$.
The graph shows the variation of the power dissipated in the resistor R with the value of the resistance R.
The maximum dissipated power is when $R$ equals the internal resistance of the battery $r$.

2.Determine the values of the internal resistance $r$ and the emf $ϵ$ of the cell.r=   ≪Ω≫
ϵ=   ≪V≫
3.1.Calculate the smallest possible reading on the ammeter.I=   ≪A≫
On the axes given, sketch the variation of the reading of the voltmeter with the reading of the ammeter for all values of the variable resistor $R$ and state the quantity represented by the gradient.

  If the current in the cx4df.,w l:hjthcp5u) ircuit below is 0.5 $A$, what is the potential difference $V$?

  In the following graph, the $V−I$ relationship for two different resistors $R_A$​ and $R_B$​ is displayed.


Which of the following statements is correct?

  A robot is used to move boxes in a factory. A box is pulled up a slope inclined at $30^{\circ}C$ to the horizontal by a rope connected to the robot. The tension T in the rope is 45$\,N$. Friction acts between the box and the ramp.


1.Define work done by a force.
2.The box is moving at a constant speed. It covers $1.2\,m$ in $3.0\,s$.
(1).Show that the output power of robot $18\,W$.v=   $ms^{−1}$
P=   W
(2).During the pull, the robot has a potential difference of $24\,V$ across the terminals of its battery and a current of $3.3V$ derived from the battery. Determine the efficiency of the robot in this situation.$P_t$=   W
$\frac{Useful Power​}{Total Powe}$=  
(3).The emf of the battery is 32 $V$. Calculate the internal resistance of the battery.
3.The rope connecting the robot and the box breaks at a height of $1.5\,m$ from the ground level.r=   Ω​
(1)The maximum height above the ground level reached by the box is $1.505\,m$. Show that the work done by friction on the box after the break up to reach the maximum height is $0.15\,J$.$W_f$=   J
(2)Determine the coefficient of dynamic friction between the box and the incline.μ=  
The box experiences friction both on the way up the slope and also as it slides back down the slope. On the graph below, sketch the variation of the speed $v$ of the box with the time $t$ passed from when the rope breaks until the box reaches the ground level.

  The circuit shown is used to measure the variation of the resistance R of a wire with the length L of the wire. The wire is connected across points X and Y.




A voltmeter and an ammeter are connected to the circuit in order to investigate the relationship.
(1).Draw the ammeter and voltmeter on the given circuit with their correct connections.
(2).State the purpose of connecting a resistor in series with the wire as shown in the diagram.

2.The diameter d of the wire is kept constant at $d=0.58±0.01\,mm$. Determine the percentage uncertainty of the cross sectional area A of the wire.A=  
3.The graph shows the variation of resistance of the wire R with the wire's length L.

(1).Draw the line of best fit.
(2).Use the graph to estimate the resistivity of the wire.ρ=   $ \times10^{-6}Ωm$

  1.A student investigates the magnetic field produced by a coil by constru3 az:p ndim dq8xv:8j*cting a circuit with a cell of a3dvz8i: :jdnxpq* m8emf $12V$ with non-negligible internal resistance, a variable resistor, a coil, and connecting wires with negligible resistance.





The length of the copper wire used for constructing the coil is $9.4m$.
（1）Explain why the potential difference across the cell is less than $12V$ when the cell is connected to the circuit.
（2）The resistance of the variable resistor $R$ and the internal resistance of the battery $r$ are $2.5\,Ω$ and $0.025\,Ω$, respectively. The potential difference across the coil is $8.2V$. Calculate the resistance per metre of the coil. R=   $Ωm^{−1}$
（3）A compass is placed on top of the wire at point $P$, as shown in the following diagram. Deduce the direction of the magnetic field in the location of the compass.

2.The resistance of the variable resistor is gradually decreased to zero. On the axes below, sketch the variation of potential difference across the battery $V$ with the current passing through the coil $I$ as the variable resistor is moved through its full range.

  A battery of emf $ϵ$ and an internal resistance $r$ is connected across a resistance R. The total power dissipated in the circuit is P.
An identical resistor and an identical battery are added in series to the circuit. What is the new total power dissipated in this circuit?

  The circuit below consistsv)d -uw n8zfb2 of a cell and two identical resistors in parallel, with an ideal ammetez)fwd2- vunb 8r in one of the branches. The current in this branch is $I_1$​ and the current in the other branch is $I_2$​.


If the ideal ammeter is replaced by a real ammeter, what will be the effect on currents $I_1$​ and $I_2​$?

  Three resistors with re8zswpza3 7pf5 sistances $10\,Ω$,$20\,Ω$ and $30\,Ω$ are connected with two cells as shown.