Explain why birds can sit on power lineshl pv l7w)m-t etp-4a, safely, whereas leaning a metal ladder up against a power line to fetch a stuck kite is extrem, pew7al- mv-htt4p) lely dangerous.

Discuss the advantages and llq.+ iy90jf zdisadvantages of Christmas tree lights connected in parallel vllfjy90+.i zqersus those connected in series.

If all you have is a 120-V line, would ,:az+jfp by c0it be possible to light several 6-V lamps without burning them out? Howp0, bf:+jca yz?

Two lightbulbs of resib4of/3l c5m u;pv+t0ek) mholstance $R_1$ and $R_2(R_2>R_1)$ are connected in series. Which is brighter? What if they are connected in parallel? Explain.

Household outlets are often do.1tzacbqso( vd m 7 gl+:jdz0)uble outlets. Are these connected in series or parallel? How d+l0b :7c ddt.) (g1osamjqzvzo you know?

With two identical lightbulbs and two identicadv *h1aln8k5 ltj 3l1al batteries, how would you arrange the bulbs and batteries in a cd althlk11*al nv5j8 3ircuit to get the maximum possible total power out? (Assume the batteries have negligible internal resistance.)

If two identical resistors are connected in series to a bnjvmc;u,qai z- ru(42 attery, does the battery have to supp4qm r,i nuav( zu2-;cjly more power or less power than when only one of the resistors is connected? Explain.

You have a single 60-W bulb g.* +qtby0k bsw2zr9i/)fxz czx66gi on in your room. How does the overall resistance of your room’s electric circuit change when you turn on an additional 100-W bulibf6tw/y q .0i2gsz) +k*rzgcx x 9b6zb?

When applying Kirchhoff’s loop rule (such as in w 37 o(qhqvya3xf-,u;6kabo:t-iy lv Fig. Below), does the sign (or direction) of a battery’s emf depend on the direction of current through the battery? What about the te ;quv i3,t-3f:y oxow7akab(qy-h l6vrminal voltage?

  Given the circuit shown in Fig. 19–364b et7cy08+ea sehbd) ze52hl,e c)i m, use the words “increases,” “decreases,” or “stays the same” to complete the)s c z0 iteee2be4eam+by,ch)7 l58dh following statements:
(a) If $R_7$ increases, the potential difference between A and E  ----待选择----stays in samedecreaseincrease . Assume no resistance in Ann meter and power supply.
(b) If $R_7$ increases, the potential difference between A and E  ----待选择----stays in samedecreaseincrease . Assume Ann meter and power supply have resistance.
(c) If $R_7$ increases, the voltage drop across $R_4$  ----待选择----stays in samedecreaseincrease .
(d) If $R_2$ decreases, the current through $R_1$  ----待选择----stays in samedecreaseincrease .
(e) If $R_2$ decreases, the current through $R_6$  ----待选择----stays in samedecreaseincrease .
(f) If $R_2$ decreases, the current through $R_3$  ----待选择----stays in samedecreaseincrease .
(g) If $R_5$ increases, the voltage drop across $R_2$  ----待选择----stays in samedecreaseincrease .
(h) If $R_5$ increases, the voltage drop across $R_4$  ----待选择----stays in samedecreaseincrease .
(i) If $R_2$,$R_5$, and $R_7$ increase, power supply (r = 0)  ----待选择----stays in samedecreaseincrease .

For what use are batteries connected in series? For what use are taisq+f;o:ytwe4s)+ dxp4y 8i hey connected in parallel? Does it matter if the batteries are nearly identical or)8+ :qyfisw4 yea+4t sdpx o;i not in either case?

Can the terminal voltage of a battery ever exceed its emf? Explae bw7kh;9ki:pkg,u 4v in.

Explain in detail how you could measure the internal resistance of a battery 9*iagi5f7i6kvdv *q45z sfvt.

Compare and discuss the formulas forgwco.(r620 gcd yp y(d resistors and for capacitors when connected in w dgc(2.6p0ygoc(rd yseries and in parallel.

Suppose that three identiuca5*ncy pvu48 5oon9 +fm8macal capacitors are connected to a battery. Will they store more e85ucc+8*o5yanfpom4 nv au 9mnergy if connected in series or in parallel?

Why is it more dangerous to turn on an electric appliance when you atlyb;9 :ut3p nw (m5x8z j:rfnre standing outsidep8 brnn3t ywtz jluf; 5m9x::( in bare feet than when you are inside wearing shoes with thick soles?

(Fig. Below) is a diagram of a capacitor (or condenser) micrhw6bdctc64 ;3l-3 ai0goobot ophone. The changing air pressure in a sound wave causes one plate of the capacitor C to move back o 6a3- t c0dtwogihlb64 boc;3and forth. Explain how a current of the same frequency as the sound wave is produced.

Design a circuit in which two different switches of the type shown in (Fig. e05bi3;yt hesh6do x 0Below) can be used to operate the same lightbulb from opposite sides of a y0sb0it 6hehe ;d5xo3room.

In an RC circuit, currentp5q t3qsb1m;9 u/7/qpwgv q5ubtv5qm flows from the battery until the capacitor is completely charged. Is the total energy supplied by the battery equal to the total energy stored by the capacitor? If not, where does the extra energy 9v57qvqp g;m tsqu5u w1 t3/ bpqq/b5mgo?

What is the main difference betw/+vv2sidly 6 ween an analog voltmeter and an analog ammeter?

What would happen if a 8xrmlo15-kbyou mistakenly used an ammeter where you needed to use a voltmeterma8lo15r kx b-?

Explain why an ideal ammeter would hava4w, ;ao vs m(wyve2s1+ln cl/b3tto9e zero resistance and an ideal voltmeter infini4+s1o yt(we 2m cv93s/t anlo,v lwba;te resistance.

A voltmeter connected across a regq 7lndn9bb-7 g 1ftd/sistor always reads less than the actual voltage across the resistor when the meter is not prese 7nqt gblfg9d-/db1n7nt. Explain.

A small battery-operate .dn r3i2dtn,hfj.m+ yd flashlight requires a single 1.5-V battery. The bulb is barely glow nm.tdhd+infrj2y3, .ing, but when you take the battery out and check it with a voltmeter, it registers 1.5 V. How would you explain this?

  Calculate the terminal voltage for a battery with an into(g)cgoe 4 kqj d9rpli(5 wv1/ernal resistance of $0.900\Omega$ and an emf of $8.50\,V$ when the battery is connected in series with
(a) an $81.0-\Omega$ resistor,    V
(b) an $810-\Omega$ resistor.    V

  Four $1.5-V$ cells are connected in series to a $12-\Omega$ lightbulb. If the resulting current is $0.45\,A$, what is the internal resistance of each cell, assuming they are identical and neglecting the wires?    $\Omega$

  What is the internal resistis 2n)3 c0h3lnb-iu isance of a $12.0-V$ car battery whose terminal voltage drops to $8.4\,V$
when the starter draws $75\,A$?    $\Omega$
What is the resistance of the starter?    $\Omega$

  A $1.5-V$ dry cell can be tested by connecting it to a low-resistance ammeter. It should be able to supply at least $22\,A$. What is the internal resistance of the cell in this case, assuming it is much greater than that of the ammeter?    $\Omega$

  Four $240-\Omega$ lightbulbs are connected in series.
What is the total resistance of the circuit?    $\Omega$
What is their resistance if they are connected in parallel?    $\Omega$

  Three $45-\Omega$ lightbulbs and three $75-\Omega$ lightbulbs are connected in series.
(a) What is the total resistance of the circuit?    $\Omega$
(b) What is their resistance if all six are wired in parallel?    $\Omega$

  A $650-\Omega$ and a $2200-\Omega$ resistor are connected in series with a $12-V$ battery. What is the voltage across the $2200-\Omega$ resistor?    V

  Given only one $25-\Omega$ and one $35-\Omega$ resistor, list all possible values of resistance that can be obtained.    $\Omega$    $\Omega$    $\Omega$    $\Omega$

  Suppose that you have6gzq, -ro:m2cn7kf je a $680-\Omega$, a $940-\Omega$ and a $1.20-k\Omega$ resistor. What is
(a) the maximum,    $\Omega$
(b) the minimum resistance you can obtain by combining these?    $\Omega$

Suppose that you have adyg ,;deb ;hrdl/i;6 k $6.0-V$ battery and you wish to apply a voltage of only $4.0\,V$. Given an unlimited supply of $1.0-\Omega$ resistors, how could you connect them so as to make a “voltage divider” that produces a $4.0-V$ output for a $6.0-V$ input?

  Three $240-\Omega$ resistors can be connected together in four different ways, making combinations of series and/or parallel circuits. What are these four ways, and what is the net resistance in each case?
The resistors can all be connected in series   $\Omega$
The resistors can all be connected in parallel.   $\Omega$
Two resistors in series can be placed in parallel with the third.   $\Omega$
Two resistors in parallel can be placed in series with the third.    $\Omega$

  A battery with an emf of a vnm*z /rrvq9 j1vt55$12.0\,V$ shows a terminal voltage of $11.8\,V$ when operating in a circuit with two lightbulbs rated at $3.0\,W$ (at $12.0\,V$) which are connected in parallel. What is the battery’s internal resistance?    $\Omega$

  Eight identical lights are connected in series across apw p;zw,t jd5,aguk d+-ai4 d9 $110-V$ line.
(a) What is the voltage across each bulb? V$\approx$    V(Round to the nearest integer)
(b) If the current is $0.50\,A$, what is the resistance of each bulb, and what is the power dissipated in each?
R $\approx$    $\Omega$(Round to the nearest integer)
P $\approx$    W(retain one decimal places)

  Eight lights are connected in parallet1k-2e ,rj c0rh.mt 8fwfth p2l to a $110-V$ source by two long leads of total resistance $1.6-\Omega$. If $240\,mA$ flows through each bulb, what is the resistance of each, and what fraction of the total power is wasted in the leads?$V_R $    $\Omega$   

  Eight $7.0-W$ Christmas tree lights are connected in series to each other and to a $110-V$ source. What is the resistance of each bulb?    $ \Omega$

  A close inspection of an electric circuit twwdl 1t:ouk)j)d a8)reveals that a $480-\Omega$ resistor was inadvertently soldered in the place where a $320-\Omega$ resistor is needed. How can this be fixed without removing anything from the existing circuit?    $\Omega$

  Determine
(a) the equivalent resistance of the circuit shown in (Fig. Below),
$R_{eq}$   $\Omega$
$V_{470}$    V
(b) the voltage across each resistor. $V_{parallel}$    V

  A $75-W$, $110-V$ bulb is connected in parallel with a 40-W, 110-V bulb. What is the net resistance?    $\Omega$(Round to the nearest integer)

  Consider the network of j5-peemy8o5 5j)liqp resistors shown in (Fig. Below). Answer qualitatively: eo5m55yjeji )p-l qp8
(a) What happens to the voltage across each resistor when the switch S is closed? $V_1$  ----待选择----increasedecrease  $V_2$  ----待选择----increasedecrease  $V_3$  ----待选择----increasedecrease  $V_4$  ----待选择----increasedecrease 
(b) What happens to the current through each when the switch is closed? $V_1$  ----待选择----increasedecrease  $V_2$  ----待选择----increasedecrease  $V_3$  ----待选择----increasedecrease  $V_4$  ----待选择----increasedecrease 
(c) What happens to the power output of the battery when the switch is closed?  ----待选择----increasedecrease 
(d) Let $R_1=R_2=R_3=R_4=125\Omega$ and $V\,=\,22.0\,V$. Determine the current through each resistor before and after closing the switch. Are your qualitative predictions confirmed? Notice that the current through each of the parallel resistors is half of the total current, within the limits of significant figures. $I_1$    A $I_3$    A $I_4$    A Notice that the current through each of the parallel resistors is one third of the total current, within the limits of significant figures.$I_1$    A $I_2$    A $I_3$    A $I_4$    A  ----待选择----YesNo 

  What is the net resistance of the circuit connected to the bag7uj-u.ttk cuv ub;;7ttery in (Fig. Below)? Each resistance hc7vj- g;u7u.;u ttukbas $R\,=\,2.8K\Omega$.   k$\Omega$(retain one decimal places)

  Three equal resistors (R) are connected to a battery as shownl4a w zhfuwt52m6.ro3 in (Fig. Below). Qualitatively, what happens zhr uo5236 lw4awtf .mto
(a) the voltage drop across each of these resistors, $V_{left}$  ----待选择----decreaseincrease0  $V_{right}$  ----待选择----decreaseincrease0  $V_{right}$  ----待选择----decreaseincrease0 
(b) the current flow through each, $I_{left}$  ----待选择----decreaseincrease0  $I_{right}$  ----待选择----decreaseincrease0  $I_{right}$  ----待选择----decreaseincrease0 
(c) the terminal voltage of the battery, when the switch S is opened, after having been closed for a long time? terminal voltage  ----待选择----decreaseincrease0 
(d) If the emf of the battery is 15.0 V, what is its terminal voltage when the switch is closed if the internal resistance is $0.50\Omega$ and $R\,=\,5.5\Omega$?
$V_{terminal\,closed}$    V
(e) What is the terminal voltage when the switch is open? $V_{terminal\,closed}$    V

  A $2.8-k\Omega$ and a $2.1-k\Omega$ resistor are connected in parallel; this combination is connected in series with a $1.8-k\Omega$ resistor. If each resistor is rated at $\frac{1}{2}W$ (maximum without overheating), what is the maximum voltage that can be applied across the whole network?    V

  Calculate the current in the circuit of (Fuh k//of2r e z9u5(/(xlhq nuxlc+*glig. Below) and show that the sum of all the voltage ch fnzlhq/h(lug klc2*/x+(exu/5 u9o ranges around the circuit is zero.
I $\approx$    A(retain two decimal places)
$\sum$    V

  Determine the terminal nrt9zzgyo )1xx -o:d 0w6jdu/voltage of each battery in (Fig. Below). 18V battery    V 12V battery    V

  (a) What is the potential difference between points a and d in (Fig. Below a) ob 2ko(s2/usx.mqy;ht)) hl y (same circuit as Fig. Below b,k)u/h2;yo ls)(otybmx h 2 .sq ), $V_{ad}$    V
(b) what is the terminal voltage of each battery?
80V battery    V
45V battery    V

a
b

  For the circuit shown in (Fig0,pb(ff tm.kz*uxjp/iy i e /o*j6wfmz .x7c +. Below), find the potential difference between points 0 /w,fkz*.om(mjjuey* p/.if zif 7 x6cp+xtb a and b. Each resistor has $R\,=\,75\Omega$ and each battery is 1.5 V.    V

  Determine the magnitudes and directions of the cb29 us f3b06tm zmnxo,urrents through $R_1$ and $R_2$ in (Fig. Below). $I_1$    A  ----待选择----leftright  $I_2$    A  ----待选择----leftright 

  Repeat Problem 27, now assuming that each battka l-u4ve au1w j;yx,3yml8a)ery has an internal resistance $r\,=\,1.2\Omega$.
$I_1$ $\approx$    A  ----待选择----leftright (retain two decimal places)
$I_2$ $\approx$    A  ----待选择----leftright  (retain two decimal places)
$I_3$ $\approx$    A  ----待选择----leftright  (retain two decimal places)

  Determine the magnitudes and directions of the currents in each resist6bnd mgz 1x(:ujsc 45ior shown in (Fig. Below). The batteries havz gc51ium bxdn:6(sj4 e emfs of $E_1\,=\,9.0V$ and $E_2\,=\,12.0V$ and the resistors have values of $R_1\,=\,25\Omega$,$R_2\,=\,18\Omega$, and $R_3\,=\,35\Omega$
$I_1$ $\approx$    A  ----待选择----leftrightup (retain two decimal places)
$I_2$ $\approx$    A  ----待选择----leftrightup  (retain two decimal places)
$I_3$ $\approx$    A  ----待选择----leftrightup  (retain two decimal places)

  Repeat Problem 29, assuming each battery has internal resisn2v e h k*u2fjddbf9b7t9p7i8 tance $r\,=\,1.0\Omega$.
$I_1$ $\approx$    A  ----待选择----leftrightup (retain two decimal places)
$I_2$ $\approx$    A  ----待选择----leftrightup  (retain two decimal places)
$I_3$ $\approx$    A  ----待选择----leftrightup  (retain two decimal places)

  Calculate the currents in each resistor of Fig. 19–ue3 zi2-t1 *p dzhp+/u1x ewie49.
$2\Omega$    A
$6\Omega$    A
$8\Omega$    A
$10\Omega$    A
$12\Omega$    A

  (a) Determine the currid2,ba+ sqs0 tents $I_1$,$I_2$, and $I_3$ in (Fig. Below). Assume the internal resistance of each battery is $r\,=\,1.0\Omega$$I_1$ $\approx$    A(retain two decimal places)
$I_2$ $\approx$    A (retain two decimal places)
$I_3$ $\approx$    A (retain three decimal places)
(b) What is the terminal voltage of the 6.0-V battery? $V_{terminal}$    V

  What would the current a/vuu(7 q hwgzl-0xe8 $I_1$ be in (Fig. Below) if the $12-\Omega$ resistor is shorted out? Let $r\,=\,1.0\Omega$. $I_1$    A

  Suppose two batteries, with u 4dupa6. f;iabnequal emfs of 2.00 V and 3.00 V, are connected as shown in (Fig. Below). If each internal resistance is . ai;4u6fpabd$r\,=\,0.100\Omega$ and $R\,=\,4.00\Omega$, what is the voltage across the resistor R? $V_R$ $\approx$    V (retain two decimal places)

  (a) Six $4.7-\mu F$ capacitors are connected in parallel. What is the equivalent capacitance? $C_{eq}$ =    $\mu F$
(b) What is their equivalent capacitance if connected in series? $C_{eq}$ =    $\mu F$

  You have three capacitors, of capaci) n2gm7lkst g5tance 3200 pF, 7500 pF, and $0.0100\mu F$ . What maximum and minimum capacitance can you form from these? How do you make the connection in each case?
$C_{max}$ =    $ \times10^{-8 }\;F$ in  ----待选择----parallelseries 
$C_{min}$ =    $ \times10^{-9 }\;F$ in  ----待选择----parallelseries 

  A $3.00-\mu F$ and a $4.00-\mu F$ capacitor are connected in series, and this combination is connected in parallel with a $2.00-\mu F$ capacitor (see Fig. Below). What is the net capacitance? $C_{eq}$ =    $\mu F$

  If 26.0 V is applied across the whole -xms: t;q ri9ufjh*f4network of (Fig. Below), calculate the voltage across each capaci-ut ; rj:ihf 9q*mf4xstor.
$V_{2.00}$    V
$V_{3.00}$    V
$V_{4.00}$    V

  The capacitance of a portiock mx;i w5v( cptw/)o+/0y xgcn of a circuit is to be reduced from 4800 pF to 2900 pF.mcx+ow(cc5y0v g/)w; t/ pxki
What capacitance can be added to the circuit to produce this effect without removing existing circuit elements?    $ \times10^{ -9}\;F$
Must any existing connections be broken in the process?  ----待选择----YesNo 

  An electric circuit was acci76p , gpswjg m-;ps6qh 3jjkx(dentally constructed using a $5.0-\mu F$ capacitor instead of the required $16-\mu F$ value. Without removing the $5.0-\mu F$ capacitor, what can a technician add to correct this circuit?    $\mu F$ conneected in  ----待选择----parallelseries 

Determine the equivalent capacitance of the circuit s 3 td8 .v+ri ncg//eeunqa0,mwhown in (Fig. Below).

  In (Fig. Below), if 0 (6m kdkwjom;.elbd- $C_1=C_2=2C_3=22.6\mu F$, how much charge is stored on each capacitor when $V\,=\,45.0V$?
$Q_1$   $ \times10^{-3 }\;C$
$Q_2$   $ \times10^{-4 }\;C$
$Q_3$   $ \times10^{-4 }\;C$

  In (Fig. Below), supp)f lx44wibei :ose $C_1=C_2=2C_3=16.0\mu F$, If the charge on $C_2$ is $Q_2\,=\,24.0\,\mu C$, determine the charge on each of the other capacitors, the voltage across each capacitor, and the voltage V across the entire combination.
$ Q_{1}$ =    $\mu C$, $V_{1}$=   V
$ Q_{2}$ =    $\mu C$, $ V_{2}$=    V
$ Q_{3}$ =   $\mu C$, $ V_{3}$=    V
V=    V

  In (Fig. Below), letd4;.etdn qan(i6sup, $V\,=\,78V$ and $C_1=C_2=2C_3=7.2\mu F$. How much energy is stored in the capacitor network?    $ \times10^{-2 }\;J$

  A $0.40-\mu F$ and a $0.60-\mu F$ capacitor are connected in series to a 9.0-V battery. Calculate
(a) the potential difference across each capacitor,
$V_1$    V
$V_2$    V
(b) the charge on each. $Q_1$    $ \times10^{-6 }\;C$
(c) Repeat parts (a) and (b) assuming the two capacitors are in parallel.
$V_1$    V
$V_2$    V
$Q_1$    $ \times10^{-6 }\;C$
$Q_2$    $ \times10^{-6 }\;C$

Three conducting plates, eac :bcb3dtcmff inr /402h of area A, are connected as shown in (Fig. Below). 43f 0mc r b:in/2fbcdt
(a) Are the two capacitors formed connected in series or in parallel?
(b) Determine C as a function of $d_1$,$d_2$, and A. Assume $d_1+d_2$ is much less than the dimensions of the plates.

  A circuit contains a single 250-pF capacitor hooked across a battery. Itstws. 7) qw233 pvhnuejsv-8t is desired to storesuvs-8 tj)3ehpn t.qw 327wvs three times as much energy in a combination of two capacitors by adding a single capacitor to this one.
How would you hook it up? ----待选择----parallelseries 
what would its value be?    pF

  A 185-pF capacitor is connected in series with an unknown capac6u+ s 08ssgarhitance, and as a series combination they are connected to a battery with an emf of 25.0 V. Iusa0h 86ss r+gf the 185-pF capacitor stores 125 pC of charge on its plates, what is the unknown capacitance?    pF

  Electrocardiographs are often connected as shown in (Fig. Below). The leads urb01chy1h gi m0 :ugb.s4vq0xe ny.. are said to be capacs0i 1vqry4.ug 1y0hmx.c :b.egbunh0itively coupled. A time constant of 3.0 s is typical and allows rapid changes in potential to be recorded accurately. If $C\,=\,3.0\mu F$, what value must R have? [Hint: consider each leg as a separate circuit.]    $ \times10^{6 }\;\Omega$

  In Fig. Below a (same as F7u tj2* 6tjzve/b22*tvunv; b.vqmviig. Below b), the total resistance is $15.0k\Omega$, and the battery’s emf is 24.0 V. If the time constant is measured to be $35.0\mu s$, calculate
(a) the total capacitance of the circuit    $ \times10^{-9 }\;F$
(b) the time it takes for the voltage across the resistor to reach 16.0 V after the switch is closed.    $ \times10^{-5 }\;s$

a
b

  The RC circuit of Fig. Below a (s( vma,:xp6.1 )eacddawiv0x mame as Fig. Below b) has $R\,=\,6.7k\Omega$ and $C\,=\,3.0\,\mu F$. The capacitor is at voltage $V_0$ at $t=0$. when the switch is closed. How long does it take the capacitor to discharge to 1.0% of its initial voltage?    $ \times10^{ -2}\;s$
a
b

  Two resistors and two uncharged capacitors are arranged as shown in (Fig. Below krfne0 l2 s 3cz0lj5t,1c9fjf). Then a potential difference of 24 V is ej,trf5n s2l c03kf9f1c0zjl applied across the combination as shown.
(a) What is the potential at point a with switch S open? (Let $V=0$ at the negative terminal of the source.)    V
(b) What is the potential at point b with the switch open?    V
(c) When the switch is closed, what is the final potential of point b?    V
(d) How much charge flows through the switch S after it is closed?    $\mu F$

  What is the resistance of a voltmeter on the 250-V scale if the ma, -bbqozrr *1eter sensitivity z,rb*qboar- 1 is $30,000\,\Omega/V$?    $ \times10^{6 }\;\Omega$

  An ammeter has a sensitiv,gl+mjdjhf: e:hm. / qity of $20,000\,\Omega/V$? What current in the galvanometer produces full-scale deflection?    $\mu A$

  A galvanometer has an internal m8lg bl ,a:ke4resistance of $30\Omega$ and deflects full scale for a $50-\mu A$ current. Describe how to use this galvanometer to make
(a) an ammeter to read currents up to 30 A,    $ \times10^{-5 }\;\Omega$
(b) a voltmeter to give a full-scale deflection of 250 V.    $ \times10^{6 }\;\Omega$

  A galvanometer has a sensiq8.kn1 ui bfw5 ek7ejw,ab c;78mb 7kmu)pz ,btivity of $35k\Omega/V$ and internal resistance $20.0\Omega$. How could you make this into
(a) an ammeter that reads 2.0 A full scale,
   $ \times10^{-4 }\;\Omega$ in
 ----待选择----parallelseries 
(b) a voltmeter reading 1.00 V full scale?
   k$\Omega$
 ----待选择----parallelseries 

  A milliammeter reads 10 mA full scale. Itddtsf , est5a)-;j-9ll*egi a n5c:zj consists of a $0.20-\Omega$ resistor in parallel with a $33-\Omega$ galvanometer. How can you change this ammeter to a voltmeter giving a full-scale reading of 10 V without taking the ammeter apart? What will be the sensitivity ($\Omega/V$) of your voltmeter?
$R_{ser}$ $\approx$    $\Omega$(Round to the nearest integer)
The sensitivity is    $\Omega/V$

  A 45-V battery of negligible internal resistance is connectedn7od0i6fe0do el/5 ad to a $R_1$=$38-k\Omega$ and a $R_2$=$27-k\Omega$ resistor in series. What reading will a voltmeter, of internal resistance $95k\Omega$ give when used to measure the voltage across each resistor? What is the percent inaccuracy due to meter resistance for each case?
$V_1$$\approx$    V (retain one decimal places) % error    % too  ----待选择----uplow 
$V_2$$\approx$    V (Round to the nearest integer) % error    % too  ----待选择----uplow 

  An ammeter whose internal2-gl7ku o7nj ,8rbffb resistance is $63\Omega$ reads 5.25 mA when connected in a circuit containing a battery and two resistors in series whose values are $750\Omega$ and $480\Omega$. What is the actual current when the ammeter is absent?    $ \times10^{ -3}\;A$

  A battery with $E\,=\,12.0V$ and internal resistance $r\,=\,1.0\Omega$ is connected to two $9.0-k\Omega$ resistors in series. An ammeter of internal resistance $0.50\Omega$ measures the current, and at the same time a voltmeter with internal resistance $15k\Omega$ measures the voltage across one of the $9.0-k\Omega$ resistors in the circuit. What do the ammeter and voltmeter read?
$I_{source}$   $ \times10^{ -4}\;A$
$V_{meter}$    V

  Two $9.4-k\Omega$ resistors are placed in series and connected to a battery. A voltmeter of sensitivity $1000\Omega/V$ is on the 3.0-V scale and reads 2.0 V when placed across either resistor. What is the emf of the battery? (Ignore its internal resistance.) $\approx$    V（Round to the nearest integer）

  What internal resistanco(h og6qiru g1ytbt-qjn/x.vy1 9; qqvl6q*0e should the voltmeter of Example 19–15 have to be in error by less than 3%;/tq jvg1xuqirq .lbngy*qy 660h 91to v oq-(? $\approx$    k$\Omega$

  When the resistor R in (Fauk e (jad uh6(yv e7bdi3o:8g/;xdaxax)-0mig. Below) is $35\Omega$, the high-resistance voltmeter reads 9.7 V. When R is replaced by a $9.0-k\Omega$ resistor, the voltmeter reading drops to 8.1 V. What are the emf and internal resistance of the battery?
r $\approx$    $\Omega$(retain one decimal places)
$\varepsilon$ $\approx$   V(retain one decimal places)

  Suppose that you wish to apply a 0.25-V potential differe 9va k4c7,fnhx)ju yu7nce between two points on the human 9ujacxh7v) 7kf,ny u4body. The resistance is about $2000\Omega$, and you only have a 9.0-V battery. How can you connect up one or more resistors to produce the desired voltage?    k$\Omega$

  A three-way lightbulb can produce 50 W, 100 W, ol9cppc(o o9/ 7nm; slrr 150 W, at 120 V. Such a bulb contains two filaments that can be connected to the 120 V(;/onml7src o p9c l9p individually or in parallel.
(a) Describe how the connections to the two filaments are made to give each of the three wattages.
50 W output use  ----待选择---- higher-resistance filament lower-resistance filamentfilaments in parallel 
100 W output use  ----待选择---- higher-resistance filament lower-resistance filamentfilaments in parallel 
150 W output use  ----待选择---- higher-resistance filament lower-resistance filamentfilaments in parallel 
(b) What must be the resistance of each filament?
$R_{50W}$    $\Omega$
$R_{100W}$    $\Omega$

  Suppose you want to run some appara xro(.qv,jo( 6ckj0 gotus that is 95 m from an electric outlet. Each of the wires connecting your apparatus to the 120-V source (o c(j kx,rgo.60ojvqhas a resistance per unit length of $0.0065\Omega/m$. If your apparatus draws 3.0 A, what will be the voltage drop across the connecting wires and what voltage will be applied to your apparatus?
$V_{wires}$    V
the voltage applied to the apparatus is $\approx$    V(Round to the nearest integer)

  Electricity can be a hazard in hospitals, particularly to pa9 )mqwsinf70l/k2.exkfs*. ms iuxw1tients who are connected to electrodes, such as an ECG. mf7i)l us.xfwkqs.*mi x w/n e2 09k1sFor example, suppose that the motor of a motorized bed shorts out to the bed frame, and the bed frame’s connection to a ground has broken (or was not there in the first place). If a nurse touches the bed and the patient at the same time, she becomes a conductor and a complete circuit can be made through the patient to ground through the ECG apparatus. This is shown schematically in Fig. 19–60. Calculate the current through the patient. $\approx$    $ \times10^{-3 }\;A$(retain three decimal places)

  How much energy must a 45-V bati b;c1 ok +b9kpii5ij6foy//r2y lnq+6vg4u ktery expend to charge a $0.40-\mu F$ and a $0.60-\mu F$ capacitor fully when they are placed
(a) in parallel,    $ \times10^{-3 }\;J$
(b) in series?    $ \times10^{-4 }\;J$
(c) How much charge flowed from the battery in each case?
$Q_a$    $\mu C$
$Q_b$ $\approx$    $\mu C$(Round to the nearest integer)

  A heart pacemaker is designed to operata6j yi-p5uy 37j4 lfsye at 72 beats/min using a $7.5-\mu F$ capacitor in a simple RC circuit. What value of resistance should be used if the pacemaker is to fire (capacitor discharge) when the voltage reaches 63% of maximum?    $ \times10^{-5 }\;\Omega$

  Suppose that a person’s bahc:9aqomfq w3n(/- xdwg;i 1ody resistance is $950\Omega$
(a) What current passes through the body when the person accidentally is connected to 110 V?   A
(b) If there is an alternative path to ground whose resistance is $45\Omega$, what current passes through the person?   A
(c) If the voltage source can produce at most 1.5 A, how much current passes through the person in case (b)? $\approx$    mA(retain three decimal places)

  A Wheatstone bridge is a type of “brid1*bbao 8(mw-2f avjtg ge circuit” used to make measurements of resistance. The unknowbb gwj1ma*(o 2-avtf 8n resistance to be measured, $R_x$, is placed in the circuit with accurately known resistances $R_1$ ,$R_2$, and $R_3$(Fig. Below). One of these, $R_3$, is a variable resistor which is adjusted so that when the switch is closed momentarily, the ammeter Ann Meter shows zero current flow.
(a) Determine $R_x$ in terms of $R_1$ ,$R_2$, and $R_3$.
(b) If a Wheatstone bridge is “balanced” when $R_1\,=\,630\Omega$,$R_2\,=\,972\Omega$, and $R_3\,=\,42.6\Omega$, what is the value of the unknown resistance?    $\Omega$

  An unknown length ofm4;n.e.b hdxo *mltmkbek04. platinum wire 0.920 mm in diameter is placed as the unknown rnlhm* ek. .eo tb b4xm0m.k4d;esistance in a Wheatstone bridge (see Problem 71;Fig. Below). Arms 1 and 2 have resistance of $38.0\Omega$ and $46.0\Omega$ respectively. Balance is achieved when $R_3$ is $3.48\Omega$ How long is the platinum wire?    m

What are the values of effective capacitance which can be o m4gzl l,r:qxwwwsqo 7qm06+(gsm)8vbtained by connectingqvm(w)owq4 8qgw,x+ l6s7gz mm0 r:ls four identical capacitors, each having a capacitance C?

  The variable capacitance of an old radio tuner consists of four plates conziefg3-5ptx 5fh8 7ni 5oh2evnected together placed alternately between four other plates, also connected together (Fig. Below). Each plate is separated from its neighbor by 1.5 mm of air. One set of plates can move so that the area of overlap of each plate varies eh-52n3 oz 7t5 ve8p5gifihf xfrom $2.0cm^2$ to $9.5cm^2$
(a) Are these seven capacitors connected in series or in parallel?  ----待选择----parallelseries 
(b) Determine the range of capacitance values. from    pF to    pF

  A battery produces 40.8 (zv +r,rq27y7xnsx p sV when 7.40 A is drawn from it and 47.3 V when 2.20 A is drawn. What are the emf and inter rvr (yqpn2zsx,s7+x 7nal resistance of the battery?
r    $\Omega$
$\varepsilon$    V

  How many $\frac{1}{2}-W$ resistors, each of the same resistance, must be used to produce an equivalent $2.2-k\Omega$, $3.5-W$ resistor?    $\Omega$ resistors, each rated at ½ W, in  ----待选择----seriesparallel 
What is the resistance of each, and how must they be connected? Do not exceed $P\,=\,\frac{1}{2}W$ in each resistor.    k$\Omega$ resistors, each rated at ½ W, in  ----待选择----seriesparallel 

  The current through the 2 jkylgjbn hy+ y)b-+;$4.0-k\Omega$ resistor in (Fig. Below) is 3.50 mA. What is the terminal voltage $V_{ba}$ of the “unknown” battery? (There are two answers. Why?) [Hint: use conservation of energy or Kirchhoff’s rules.]
right $V_{ab}$    V
left $V_{ab}$    V

An air-filled parallel-pl:dfv3h1 8kp(tzv+ix+ ujr7 xw ate capacitor has capacitance $C_0$. If two identically sized dielectric slabs of dielectric constants $K_1$ and $K_2$ are inserted as shown in Fig. 19–64, what is the new capacitance? [Hint: treat this as two capacitors in combination.]

  For the circuit shown i;p8i :r1 iunbin(Fig. Below), determine
(a) the current through the 14-V battery $I_1$   $ \times10^{-5 }\;A$ ----待选择----downupward 
(b) the potential difference between points a and b, $V_a-V_b$.    V

  A solar cell, 3.0 cm square, has an output of 350 mA gf-v+y adj77k(qq aov.9v*vg at 0.80 V when exposed to full sunlight. A solar panel that delivers close +(jqqo vav7g7*gakdfv-9v. y to 1.0 A of current at an emf of 120 V to an external load is needed.
How many cells will you need to create the panel?    cells
How big a panel will you need, and how should you connect the cells to one another?    $m^2$
How can you optimize the output of your solar panel?    banks of    cells in series per bank, with the banks in  ----待选择----parallelseries  always have the panel ----待选择---- pointedturned  directly at the sun。

  A power supply has a fixed output voltagev to*cfx23nuoh; +* vy of 12.0 V, but you need $V_T\,=\,3.0V$ for an experiment.
(a) Using the voltage divider shown in (Fig. Below), what should $R_2$ be if $R_1$ is $10.0\Omega$? $\approx$    $\Omega$(retain one decimal places)
(b) What will the terminal voltage $V_T$ be if you connect a load to the 3.0-V terminal, assuming the load has a resistance of $7.0\Omega$? $\approx$    V(retain one decimal places)

  The circuit shown in (Fig. Below a) uses a neon-filled tube as in (Fig. Bel*6)wyj kv+vlcow b). This neon lamp has a threshold voltvj* +vy)l6kcw age $V_0$ for conduction, because no current flows until the neon gas in the tube is ionized by a sufficiently strong electric field. Once the threshold voltage is exceeded, the lamp has negligible resistance. The capacitor stores electrical energy, which can be released to flash the lamp. Assume that $C=0.150\mathrm{~}\mu\mathrm{F},R=2.35\times10\mathrm{~}^6\Omega,V_0=90.0\mathrm{~V}$ and Ann meter=105 V
(a) Assuming that the circuit is hooked up to the emf at time $t\,=\,0$, at what time will the light first flash?    s
(b) If the value of R is increased, will the time you found in part (a) increase or decrease?  ----待选择---- increase decrease 
(c) The flashing of the lamp is very brief. Why?
(d) Explain what happens after the lamp flashes for the first time.

a
b

  The current through avga4 kwi/f 4o ;ppk8:1sz0dethe $20-\Omega$ resistor in (Fig. Below) does not change whether the two switches $S_1$ and $S_2$ are both open or both closed. Use this clue to determine the value of the unknown resistance R.    $\Omega$

  In the circuit shown in (Fig. Bt1wz;8nk0l zh+ b2;we l :guvs :fpt/lelow), the $33-\Omega$ resistor dissipates 0.50 W. What is the battery voltage? $\approx$    V(retain one decimal places)

  (a) What is the equivalent resistance of the circusrjhv 7d8u+ c-it shown in (Fig. Below)? $R_{eq}$ $\approx$    $\Omega$(retain one decimal places)
(b) What is the current in the $18-\Omega$ resistor?    A
(c) What is the current in the $12-\Omega$ resistor?    A
(d) What is the power dissipation in the $4.5-\Omega$ resistor?   W

(a) A voltmeter and an ammeter can be connected as shown in (Figb(vxf/v9t q2aogue:/ t(d i c7. Below a) to measure a resistance R. If V is the voltmeter reading, and I is the ammeter reading, the value of R will (v 9bu /xav /t7gf(iqo:edc 2tnot quite be $V/I$ (as in Ohm’s law) because some of the current actually goes through the voltmeter. Show that the actual value of R is given by
$\frac{1}{R}=\frac{I}{V}-\frac{1}{R_\mathrm{V}}$,
where $R_V$ is the voltmeter resistance. Note that $R\approx V/I\quad\mathrm{if}\quad R_\mathrm{V}\gg R$ .
(b) A voltmeter and an ammeter can also be connected as shown in (Fig. Below b) to measure a resistance R. Show in this case that
$R=\frac{V}{I}-R_\mathrm{A},$
where V and I are the voltmeter and ammeter readings and $R_A$ is the resistance of the ammeter. Note that $R_\mathrm{A}\quad\mathrm{if}\quad R\approx V/I\quad\mathrm{if}\quad
R_\mathrm{A}\ll R.$

  A flash lightbulb rated at 2.5 W and 3.0 V is ops7xueoh*ul6(z*ui c 2nckfgx +)(ev) zv z)y (erated by a 9.0-V battery. To light the bulb at its ratf nhv+o*)euz)c)cul 2(u67k*( izyevx g z(s xed voltage and power, a resistor R is connected in series as shown in (Fig. Below). What value should the resistor have?    $\Omega$