If two points are at the same potentiaaqif8n w5f5. kk1hpywe-. ti.l, does this mean that no work is done in moving a test charge from ona.wpf8qwneh.5y-t1k.i f k i 5e point to the other? Does this imply that no force need be exerted? Explain.

If a negative charge is initially at rest in an ele0lyvdnp k0zn;) qd04uz4 p-kjctric field, will it move toward a region of higher potential or lower potential? What about a positive char-d00 lykdzv n4 up 40z)jqkp;nge? How does the potential energy of the charge change in each instance?

State clearly the difference)q (srxh u1xw( (a) between electric potential and electric field, (b) betweqs(x1 )u hx(rwen electric potential and electric potential energy.

An electron is accelerated by a potential difference of, say, 0.10 V. How muc6hbs p a//ftiv8ki; h, k93dfeh greater would its final speed be if it is accelerated with fouvt83kf/eks /hb9a dfh ,6iip ;r times as much voltage? Explain.

Is there a point along the line joining two equal pox7*.g kr8hawmsitive charges where the electric field is zero? Where the electric potential is zek.gwm *ha7xr8ro? Explain.

Can a particle ever move ax q3u-ykh:9mfrom a region of low electric potential to one of high potential and yet have its e kaxh q-3:9ymulectric potential energy decrease? Explain.

Compare the kinetic t0tg- dque.yk5i ,+t oenergy gained by a proton $(q=+e)$ to the energy gained by an alpha particle $(q=+2e)$ accelerated by the same voltage $V$.

If $V\,=\,0$ at a point in space, must $\vec{E}\,=0$ there? If $\vec{E}\,=0$ at some point, must $V\,=\,0$ at that point? Explain. Give examples for each.

Can two equipotential lines cross? Explkocf(eq 5fw 7 0/oqc5qain.

Draw in a few equipotential lines in Fig. 1joeefl - 2-jt16 – 31b.

What can you say about the electric field ini86tqta 1 qo7e a region of space that has the same potential thrtt67 o8qq 1ieaoughout?

A satellite orbits the Earth along a gravitational equipotentid;0t.lxbcbldn3 b 87kr*eq7 9q :isbxal line. What shape must the orbit b7b9x bl* kqr0bsqd7:i3de c lt.bn8x ;e?

When dealing with practical devices, we often ta2wr vorh1t v1/ke the ground (the Earth) to be 0 V. If, instead, we said the ground was 2ovhr/11wrt v how would this affect (a) the potential V, and (b) the electric field E, at other points?

When a battery is connected to a capacitor, why do the two plg0 jjt5bl ;0srates acquire charges of the same magnitude? Will this be true if the two conductors0blsr 0gj5j ;t are different sizes or shapes?

We have seen that the capacitance C depends on the size, shape, and posi+ pjgh ru9ew30bkhp8 +g,yx46fs n.v ition of the two conductors, as well as on the dielectric cos8hp jew+ ,.gr6v0xgfn4bu +i9y3hkpnstant K. What then did we mean when we said that C is a constant in Eq. 17 – 7?

  How much work does the ssox)or, 05sjek +eq*l h73gc electric field do in moving a $-7.7\mu C$ charge from ground to a point whose potential is $+55V$ higher?    $ \times10^{-4 }\,J$

  How much work does the electric field do ;gemzst+; ivk44p6hnh1 loo 9in moving a proton from a point with a potek6ti; l4+spe;v ogz4ho 9nmh1 ntial of $+125V$ to a point where it is $-55V$ Express your answer both in joules and electron volts.
   $ \times10^{-17 }\,J$
   eV

  How much kinetic energy will an electron gain (in joules and eV) if ir-j,7 thf v:tuy pw)p9t accelerates through a potential difference of 23,000 V in a TV r-pht:t) pfy9w u,v j7picture tube?
   $ \times10^{-15 }\,J$
   eV

  An electron acquireshnol3 9-qgk7 n6yvoqo -y ju4( $7.45 \times10^{ -16}\,J$ of kinetic energy when it is accelerated by an electric field from plate A to plate B. What is the potential difference between the plates, and which plate is at the higher potential?
   V
plate ----待选择----AB 

  How strong is the electric field between two parallel platesjq a-v06efefe26 j i:psi,r;y 5.8 mm apart if the potential difference between thiy2f06q jap ,jvei fes-:r;e6em is 220 V?    $ \times10^{ 4}\,V/m$

  An electric field of wlf3ugs92gbdqu4yg *23 wm i2$640V/m$ is desired between two parallel plates 11.0 mm apart. How large a voltage should be applied?    V

  The electric field between two pao ksot 65y94llrallel plates connected to a 45-V battery is $1500V/m$ How far apart are the plates?    m

  The electric field between two parallel plates connected tzl -an:dk2e 4lo a 45-V battery is $1500V/m$ How far apart are the plates?    m

  What potential difference is needed to give a helium nuclyfnmz 0bq7 8;sj (vux9e:d. o.cd x3zmeus $(Q=2e)$ 65.0 keV of kinetic energy?    $ \times10^{4 }\,V$

  Two parallel plates, connected to a 200-Vflkt1)(lt,b sst:balj e4c 51 bn-(sr power supply, are separated by an air gap. How small can the gap be if the air is not to ben5lslsrt tkf1satbb(,b :-)e l j(1 4ccome conducting by exceeding its breakdown value of $E\,=3 \times10^{ 6}\,V/m$?   $ \times10^{-5 }\,m$

  The work done by an external force to move f5a3 aymg. ie3m)px0h a $-8.50\mu C$ charge from point a to point b is $15.0 \times10^{ -4}\;J$. If the charge was started from rest and had $ 4.82\times10^{ -4}\;J$ of kinetic energy when it reached point b, what must be the potential difference between a and b?    V

  What is the speed of an we3xgu,j.tpv4cq) 8z electron with kinetic energy
(a) 750-eV,    $ \times10^{7 }\;m/s$
(b) 3.2-keV?    $ \times10^{7 }\;m/s$

  What is the speed of al,an;gp5xpg f8vet9. **ye ut proton whose kinetic energy is 3.2 keV?    $ \times10^{5}\,m/s$

  An alpha particle (which is a hel h ;/wha(ckx*:u4l0 fk pw2gasium nucleus, $Q=+2e$, $m\,=\,6.64\times10^{-27 }\,kg$) is emitted in a radioactive decay with $_{KE}$ = $5.53MeV$ What is its speed?    $ \times10^{7}\,m/s$

  What is the electric potential hnf3ewm (nlmfp ;6uii-1j )z, z,eh4z 15.0 cm from a $4.00\mu C$ point charge?    $ \times10^{ 5}\,V$

  A point charge Q creates an electric)rk0,kjks wzw;98uel potential of $+125V$ at a distance of 15 cm. What is Q?    $ \times10^{-9 }\,C$

  A $+35\mu C$ point charge is placed 32 cm from an identical $+35\mu C$ charge. How much work would be required to move a $+0.50\mu C$ test charge from a point midway between them to a point 12 cm closer to either of the charges?    J

Draw a conductor in tx hn vy ;brbod152ak)8q:d --k uh6ksche shape of a football. This conductor carries a net negativ-kbdr x8s1:c kqvnhy;bdauh2 56o- k)e charge, $-Q$. Draw in a dozen electric field lines and two equipotential lines.

  (a) What is the elec eawx5 vv-z((3eetfc1tric potential a distance of $ 2.5\times10^{-15 }\,m$ away from a proton?    $ \times10^{ 5}\,V$
(b) What is the electric potential energy of a system that consists of two protons $2.5 \times10^{-15 }\,m$ apart — as might occur inside a typical nucleus?    $ \times10^{ -14}\,J$

Three point charges are arrange 2ul+2zo*cu8;u-zqlg/sh fdwtc v2gw6unb 6-d at the corners of a square of side L as shown in Fig. 17–25. What is the potential atdowg-*u 2 -gwcqln2htfzu/b2ul 8;z+us 6vc 6 the fourth corner (point A), taking $V\,=\,0$ at a great distance?

  An electron starts from rest 32.5 cm from a fixed point char 8i:gss 6 n8:iylb0xauge with $Q\,=\,-0.125\mu C$. How fast will the electron be moving when it is very far away?    $ \times10^{7 }\,m/s$

  Two identical $+9.5\mu C$ point charges are initially 3.5 cm from each other. If they are released at the same instant from rest, how fast will each be moving when they are very far away from each other? Assume they have identical masses of 1.0 mg.    m/s

  Two point charges, $3.0\mu C$ and $-2.0\mu C$ are placed 5.0 cm apart on the x axis. At what points along the x axis is
(a) the electric field zero    cm leftof $q_2$
(b) the potential zero? Let $V\,=\,0$ at $r\,=\,\propto$.

  How much work must be done to bring three electrons from a great distance apart h +9;g ,q+qs o b0+r5 yo/msjk2daspchth5og+d+ o sc0/ mpbja;+2 yss,qk9qrho $1.0 \times10^{-10 }\,m$ from one another (at the corners of an equilateral triangle)?    $ \times10^{-18 }\,J$

  Consider point a which is 72 cm nort)c t (w8rq-bng,0f hgth of a $-3.8\mu C$ point charge, and point b which is 88 cm west of the charge (Fig. 17–26). Determine
(a) $V_{ba}=V_b-V_a$    V
(b) $\vec{E}_b-\vec{E}_a$ (magnitude and direction).
   V/m
   $^{\circ}\,$

  How much voltage mustekilegzk)r*k* - )*9jq b nh5p be used to accelerate a proton (radius $1.2 \times10^{-15 }\,m$) so that it has sufficient energy to just penetrate a silicon nucleus? A silicon nucleus has a charge of $+14e$, and its radius is about $ 3.6\times10^{-15 }\,m$. Assume the potential is that for point charges.    $ \times10^{6 }\,V$

Two equal but oppositevzr1a3 ra blvt3o)/;z charges are separated by a distance d, as shown in Fig. 17–27. Dete z3b/3t1arro ;zl)v varmine a formula for $V_{BA}\,=\,V_B-V_A$ for points B and A on the line between the charges.

  In the Bohr model of the hydrogen at maa*av3p+ (tmom, an electron orbits a proton (the nucleus)vp m aa+(m3t*a in a circular orbit of radius $ 0.53\times10^{-10 }\,m$.
(a) What is the electric potential at the electron’s orbit due to the proton?    V(Round to the nearest integer)
(b) What is the kinetic energy of the electron?
   $ \times10^{ -18}\,J$
   eV
(c) What is the total energy of the electron in its orbit?    $ \times10^{-18 }\,J$ $\approx$    eV(Round to the nearest integer)
(d) What is the ionization energy — that is, the energy required to remove the electron from the atom and take it to $r\,=\,\propto$, at rest? Express the results of parts b, c and d in joules and eV.   $ \times10^{-18 }\,J$    eV(Round to the nearest integer)

  An electron and a proton arpg9ibfc j,gq2 nb0 7)se $ 0.53\times10^{ -10}\,m$. apart. What is their dipole moment if they are at rest?    $ \times10^{-30 }\,C\cdot\,m$

  Calculate the electric potential due to a dipole whose gcr,s yob rqs )jtk883+g..fudipole moment is $ 4.8\times10^{-30 }\,C\cdot m$ at a point $1.1 \times10^{ -9}\,m$ away if this point is
(a) along the axis of the dipole nearer the positive charge;    V
(b) 45° above the axis but nearer the positive charge;    V
(c) $45^{\circ}\,$ above the axis but nearer the negative charge.    V

  The dipole moment, considered as a vector, points from the negative to h)mw; bsts/3ethe positive charge. The water molecule, Fig. 17–28, has a dipole moment which can be considered mbwe)/sh3 st; as the vector sum of the two dipole moments, $\vec{P}_1$ and $\vec{P}_2$as shown. The distance between each H and the O is about $ 0.96\times10^{ -10}\,m$. The lines joining the center of the O atom with each H atom make an angle of $104^{\circ}\,$, as shown, and the net dipole moment has been measured to be $p\,=\,6.1 \times10^{-30 }\,C\cdot m$ Determine the charge q on each H atom.    $ \times10^{ -20}\,C$

  The two plates of a capacitor holdb3 d g9gxq*fym i)yv0lvk 69m2 $+2500\mu C$ and $-2500\mu C$ of charge, respectively, when the potential difference is 850 V. What is the capacitance?    $ \times10^{-6 }\,F$

  The two plates of a ecbj2wg 5 + + cf-swc5i38otc1yn ;tkjcapacitor hold $+2500\mu C$ and $-2500\mu C$ of charge, respectively, when the potential difference is 850 V. What is the capacitance?    $ \times10^{-6 }\,F$

  A 9500-pF capacitor holds plus and minus1:zyebo e;*et/+ez x p charges of $ 16.5\times10^{-8 }\,C$. What is the voltage across the capacitor?    V

  The potential difference between two short sections ofy1 aa1g4udn0 .tpky:1zb by7q parallel wire in air is 120 kgqabd :yzy11b4710. pnyuta V. They carry equal and opposite charge of magnitude 95 pC. What is the capacitance of the two wires?    $ \times10^{13 }\,F$

  How much charge flows from each 7s*( htcmtkh poi*+s7terminal of a 12.0-V battery when it is connected to+stmi*hht7 kspoc 7( * a $7.00-\mu F$ capacitor?    $ \times10^{-5 }\,C$

  A 0.20-F capacitor is desired. What area must th6z-o) zpfnwdxjk+kr/ vp92t h:tu27ue plates have if they are to be separatevp 2k-:pztkju)+ dzh tw/6 noxrf79 2ud by a 2.2-mm air gap?    $ \times10^{ 7}\,m^2$

  The charge on a capacitor incre r;ub70erfcb;g8 lg7nw: bs (z0zotxxfjg52 * ases by $18\mu C$ when the voltage across it increases from 97 V to 121 V. What is the capacitance of the capacitor?    $ \times10^{ -7}\,F$

  An electric field ofmkwp+ q:qop0l, 7yb j. $8.5 \times10^{ 5}\,V/m$ is desired between two parallel plates, each of area $35\,cm^2$ and separated by 2.45 mm of air. What charge must be on each plate?    $ \times10^{ -8}\,C$

  If a capacitor has opposno78akzx2q (/ 8j (syl.ggcf fite $5.2\mu C$ charges on the plates, and an electric field of 2.0 $2.0\,kV/mm$ is desired between the plates, what must each plate’s area be?   $m^2$

  How strong is the electric field between. 9feash 3wia, the plates of a $0.80-\mu F$ air-gap capacitor if they are 2.0 mm apart and each has a charge of $72\mu C$ ?    $ \times10^{4 }\,V/m$

  A capacitor is charged by a 125-V battery (Fig. 17–29a) n zb7n09ds:ojun/ .woy*rc 8cand then is disconnected from the battery. When this 9b owu:srn.dn 0 czo8c 7yn*j/capacitor $(C_1)$ is then connected (Fig. 17–29b) to a second (initially uncharged) capacitor, $C_2$, the final voltage on each capacitor is 15 V. What is the value of $C_2$? [Hint: charge is conserved.]    $ \times10^{ -5}\,F$

  A $2.50-\mu F$ capacitor is charged to 857 V and a $6.8-\mu F$ capacitor is charged to 652 V. These capacitors are then disconnected from their batteries. Next the positive plates are connected to each other and the negative plates are connected to each other. What will be the potential difference across each and the charge on each? [Hint: charge is conserved.]
$V_{final}$ $\approx$   V(Round to the nearest integer)
$\begin{array}{l}
Q_{1}\\
\text { initial }
\end{array}$   $ \times10^{-3 }\,C$
$\begin{array}{l}
Q_{2}\\
\text { initial }
\end{array}$   $ \times10^{-3 }\,C$

  What is the capacitance of two square parallel plates 5.5 cm on a side that ar;vl j- w j/jjq9 o7sxu5-z(dipe separated by 1.8 mm of paraffin?lpxj5wv j d( i9s-q/uz jj;7-o    $ \times10^{-11 }\,F$

  What is the capacitance of a pair of circular hi pgtlc4b(7d (l 7r*cplates with a radius of 5.0 cm separated 7t l (4brl(gpci7*chdby 3.2 mm of mica?    $ \times10^{-10 }\,F$

  A 3500-pF air-gap capacitor is connected to a 22-V battery. If a piece of micax4kpi6 1g w9wf is placed between the plates, how much charge will 4fg1w9 6iw pxkflow from the battery?    $ \times10^{ -7}\,C$

  The electric field between the plates of a paper-sepg*8b y9bgm1 gaarated $(K=3.75)$ capacitor is $ 8.24\times10^{4 }\,V/m$. The plates are 1.95 mm apart, and the charge on each plate is $0.775\mu C$. Determine the capacitance of this capacitor and the area of each plate.
   $ \times10^{--9 }\,F$
   $m^2$

  650 V is applied to a 2200-pF capacitosu )gv .)fjs-yv2ne*;p : abbcn1fa)g r. How much energy is stored?    $ \times10^{-4 }\,J$

  A cardiac defibrillator is used to shock a heart that jsf1c n lz.,61vrx:l uis beating erratically. A capacitor in this device is charged to 5.0 kjf vu6:zs1c x,1 ll.rnV and stores 1200 J of energy. What is its capacitance?    $ \times10^{-5 }\,F$

  How much energy is stored by the electric fie kb3a6uvpa*lfz.z1)q 8wq z7old between two square plates, 8.0 cm on a side, separated by a 1.5-mm air gap? The charges on the plates are equal and opposite an3 aazkq87. up f*wv bq)zlz16od of magnitude $420\mu C$.    J

  A homemade capacitor is assembled by placing two 9-in. pie pans 5c2li2tk d / c3dm7z-av-hdl: u cm apart and connecting them to thkd7vz2i3-c/al lddu2: -thc m e opposite terminals of a 9-V battery. Estimate
(a) the capacitance,    $ \times10^{-12 }\,F$
(b) the charge on each plate,    $ \times10^{-11 }\,C$
(c) the electric field halfway between the plates,    V/m
(d) the work done by the battery to charge the plates.    $ \times10^{ -10}\,J$
(e) Which of the above values change if a dielectric is inserted?

A parallel-plate capacitor has fix7(;rfx dhjv. rp*dc9oed charges $+Q$ and $-Q$ The separation of the plates is then doubled.
(a) By what factor does the energy stored in the electric field change?
(b) How much work must be done in doubling the plate separation from d to 2d? The area of each plate is A.

How does the energy stored in a *kgp85. e-fyu jq:rt o7omn 8lcapacitor change if (a) the potential difference is doubled, and (b) the charge on each platef8 m-y5 nkqjogo*: ut.e7r 8lp is doubled, as the capacitor remains connected to a battery?

  A $2.70-\mu F$ capacitor is charged by a 12.0-V battery. It is disconnected from the battery and then connected to an uncharged $4.00-\mu F$ capacitor (Fig. 17–29). Determine the total stored energy
(a) before the two capacitors are connected,    $ \times10^{-4 }\,J$
(b) after they are connected.    $ \times10^{-5 }\,J$
(c) What is the change in energy?    $ \times10^{-4 }\,J$

  In a given CRT, electrons are accelerated horizontallg ,ec)v1 rrdw4y by 7.0 kV. They then pass through a uniform electr4 c d1wg),revric field E for a distance of 2.8 cm, which deflects them upward so they reach the screen top 22 cm away, 11 cm above the center. Estimate the value of E.    $ \times10^{5 }\,V/m$

  Electrons are accelerated by 6.0 kV in a CRT. The4krk-x 2l(;xtpcv +ko;vza g8 screen is 30 cm wide and is 34 cm from the 2.6-cm-long defv+xz(a;lk -to kr8pg2k ;v4xclection plates. Over what range must the horizontally deflecting electric field vary to sweep the beam fully across the screen?    $ \times10^{5 }\,V/m$ to    $ \times10^{5 }\,V/m$

  An electron starting from rest acquires 6.3 keV of KE in moving from p9wx,4 7vhyr6(ojo n9f8goroh oint A to poin n(fhho yjvo g9,8 4w7rorxo96t B.
(a) How much KE would a proton acquire, starting from rest at B and moving to point A?    keV
(b) Determine the ratio of their speeds at the end of their respective trajectories.   

  A lightning flash trans o(8gq1:gpo(qa-hf szfers 4.0 C of charge and 4.2 MJ of energy to the Earth.
(a) Across what potential difference did it travel?    $ \times10^{ 6}\,V$
(b) How much water could this boil and vaporize, starting from room temperature?    kg

  There is an electric field near the Earth’s surface whose magnitude ise2 tq)gib b2t0 er1mp/ about $150\,V/m$ How much energy is stored per cubic meter in this field?    $ \times10^{-7 }\,J/m^3$

  In a television picture tube, electrons are accj:on,i+p rh )gelerated by thousands of volts through a vacuum. If a television set were laid on its back, would electrons be able to move upward against the fori, rpn)h:jo+gce of gravity? What potential difference, acting over a distance of 3.0 cm, would be needed to balance the downward force of gravity so that an electron would remain stationary? Assume that the electric field is uniform.    $ \times10^{ -12}\,V$

  A huge 4.0-F capacitor has enough stored energy to heat 2.5 kg of water from 21/om 8-h sqhxksu*1i p vl)4j4j$^{\circ}\,C$ to 95$^{\circ}\,C$. What is the potential difference across the plates?    V

  An uncharged capacitor is connected to a 24.0-V battery until it mf(p gx8)c m-iis fully charged, after which it is disconnected from the battery. A slab of paraffin is then infc )mgpxi(m-8 serted between the plates. What will now be the voltage between the plates?    V

  Dry air will break down if the electric f0g:kz: kwr1 sfield exceeds $3.0 \times10^{6 }\,V/m$. What amount of charge can be placed on a parallel-plate capacitor if the area of each plate is $56cm^2$?    $ \times10^{-7 }\,C$

Three charges are at the corners of an equilaterahg/adea sx,07*mmfa 3l triangle (side L) as shown in Fig. 17–30. Determine the potential at the midpoint of each of the si3 fhx7 m0a,/dg*asm aedes.

  A $3.4\mu C$ and a $-2.6\mu C$ charge are placed 1.6 cm apart. At what points along the line joining them is
(a) the electric field zero,    cm left of $q_2$
(b) the electric potential zero?

  A 2600-pF air-gap capacitor is connected to a 9.0-V battery. If a piece yetu/+h a(2 eyof Pyrex glass is placed between the plates, how much charge will then flow from the battt ee(/hauy 2y+ery?    $ \times10^{-8 }\,C$

  An electron is accelerated horizontally from rest in a television picture tubpuf6riu9: u h;e by a potential difference of 5500 V. It then pass uuh;:if 6urp9es between two horizontal plates 6.5 cm long and 1.3 cm apart that have a potential difference of 250 V (Fig. 17–31). At what angle $\theta$ will the electron be traveling after it passes between the plates?    $^{\circ}\,$

A capacitor of capacitan1btq63faoajz .aee e j 1o-k12ce $C_1$ carries a charge $Q_0$. It is then connected directly to a second, uncharged, capacitor of capacitance $C_2$, as shown in Fig. 17–32. What charge will each carry now? What will be the potential difference across each?

  To get an idea how big a farad is, suppose you want to make a 1-F air-filledkc8 dz3jbr16 /2w x svx-wb+e;pr-zvy parallel-plate capacitor for a ci/exrkpcd2-x; r8zb zvy1wsw j+6v -b3rcuit you are building. To make it a reasonable size, suppose you limit the plate area to What would the gap have to be between the plates? Is this practically achievable?    $ \times10^{-16 }\,m$  ----待选择----YesNo 

  Near the surface of the Earoi cx90+h tkn(th there is an electric field of about $150\,V/m$ which points downward. Two identical balls with mass $m\,=\,0.540kg$ are dropped from a height of 2.00 m, but one of the balls is positively charged with $q_1$ = $650\mu C$ ,and the second is negatively charged with $q_2$ = $-650\mu C$. Use conservation of energy to determine the difference in the speed of the two balls when they hit the ground. (Neglect air resistance.)    m/s

  The power supply for a pulsed nitrogen ldp:v/euw bz)s otzer3x+ g i2bx5 0w:9aser has a $0.050\mu F$ capacitor with a maximum voltage rating of 30 kV.
(a) Estimate how much energy could be stored in this capacitor.    J
(b) If 12% of this stored electrical energy is converted to light energy in a pulse that is 8.0 microseconds long, what is the power of the laser pulse?    $ \times10^{5 }\,W$

  In lightning storms, th:s-qh-j)/pvavggrj v 7 -.viye potential difference between the Earth and the bottom of the thunde -rsp/:gvviy) 7 g-hvqja-jv.rclouds can be as high as 35,000,000 V. The bottoms of the thunderclouds are typically 1500 m above the Earth, and can have an area of $110km^2$ Modeling the Earth–cloud system as a huge capacitor, calculate
(a) the capacitance of the Earth–cloud system,    $ \times10^{-7 }\,F$
(b) the charge stored in the “capacitor,”    C(Round to the nearest integer)
(c) the energy stored in the “capacitor.”    $ \times10^{8 }\,J$

  In a photocell, ultraviolet (UV) light provides enough energy to some eris)2 b 5hjq. swf:7onwf6a3nm) (ruelectrons in barium metal to eject them from a surface at high speed. See Fig. 17–33. To measure the maximum energy of the electrons, another plate above the barium surface uofbn3rs 7:ear65sm( .fi2nwh))qj wis kept at a negative enough potential that the emitted electrons are slowed down and stopped, and return to the barium surface. If the plate voltage is $-3.02V$ (compared to the barium) when the fastest electrons are stopped, what was the speed of these electrons when they were emitted?    $ \times10^{6 }\,m/s$

  A point charge is / q f 7gd41bwocjz49ssm(z1ujplaced 36 cm from an identical $+33\mu C$ charge. A $-1.5\mu C$ charge is moved from point a to point b in Fig. 17–34. What is the change in potential energy? $\approx$    J (round to one decimal place)

  A capacitor is made from two 1.1-cm-diameter coins separated by a 0.y dm--shcqrtex p.68cto . 7j)15-mm-thick pie qt6- jpry- .xedm8oh7ccs.t)ce of paper $(K=3.7)$ A 12-V battery is connected to the capacitor. How much charge is on each coin?    $ \times10^{-10 }\,C$

  A $+4.5\mu C$ charge is 23 cm to the right of a $-8.2\mu C$ charge. At the midpoint between the two charges,
(a) what are the potential    $ \times10^{ 5}\,V$
(b) the electric field?    $ \times10^{6 }\,V/m$  ----待选择----leftright 

  A parallel-plate capacitor :mbo9 /suogl5with plate area $2.0cm^2$ and air-gap separation 0.50 mm is connected to a 12-V battery, and fully charged. The battery is then disconnected.
(a) What is the charge on the capacitor?    $ \times10^{ -11}\,C$
(b) The plates are now pulled to a separation of 0.75 mm. What is the charge on the capacitor now?    $ \times10^{ -11}\,C$
(c) What is the potential difference across the plates now?    V
(d) How much work was required to pull the plates to their new separation?    $ \times10^{-10 }\,J$

  A $2.5-\mu F$ capacitor is fully charged by a 6.0-V battery. The battery is then disconnected. The capacitor is not ideal and the charge slowly leaks out from the plates. The next day, the capacitor has lost half its stored energy. Calculate the amount of charge lost.    $ \times10^{-6 }\,C$

  Two point charges are fixed 4.0 cm apart from each other. Their charges bh hi01k05p i* ad0z(ogi1zpmare $Q_1$=$Q_2$=$5.0\mu C$, and their masses are $m_1=1.5mg$ and $m_2=2.5mg$
(a) If $Q_1$ is released from rest, what will be its speed after a very long time?    m/s
(b) If both charges are released from rest at the same time, what will be the speed of $Q_1$ after a very long time?    m/s

  Two charges are placed aex9av 1aoh8 3,mqaec 3s shown in Fig. 17–35 with $q_1$=$1.5\mu C$ and $q_2$=$-3.3\mu C$ Find the potential difference between points A and B.    $ \times10^{ 5}\,V$