If two points are at the same potential, does thp03mae 9kgl4 jis mean that no work is done in moving a test charge from one point to the other? Does this imply that no force need be exerteek 0jp4glma93d? Explain.

If a negative charge is initially at rest in an electric fieldpd5azlr q) (evj d6zj8-jq)u(4w7cspvru z 44 , will it move toward a region of higher potential or lower potential? What about a positive charge? How does the potential energy qd7wdj44sv5qjuu(rvc)(86 rlz-4ze ap)z p jof the charge change in each instance?

State clearly the difference (a) between electric potential and elect1 85;,he pd z(n zi,mx;supf+chtr a2bric field, (b) between electric potenti( sr,;htaz;x z8 f peidnu+c2bmh,15pal and electric potential energy.

An electron is accelerated by a potential diffejwm 9cu-qca3;s ok(y pky./,lrence of, say, 0.10 V. How much greater would its final speed be if it is accelerated with four timeskcc /m-3ayjo;(wu,slqk. 9py as much voltage? Explain.

Is there a point along the line joining two equal positive charges wh(gk/pufb)mtohh r1)kp s1,xn .ehs93 ere the electric field isu, 3 (e )npbmp1.h1x9s)tg/fohrkhks zero? Where the electric potential is zero? Explain.

Can a particle ever move from a region of low electric potential to one of hii nm3aqsiv x 6s7f+j /k(hgo8:gh potential and yet have its electric potential energy decrease? Explain.+ x /(aqjsi7vo g38hk sifm6n:

Compare the kinetic energy gained by, .ry:g+m7poply gnw7 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? Ex3 7 an5+zkld0l * qhv8vfm/rloplain.

Draw in a few equipotential lines in Fig. 16 – 3.ic; n+l *ava)jsd3 xzl2euu31b.

What can you say about the electric field in a region of 9 6m-zapl:p)yvr8pf zspace that has the same poty9)6p r-pzplaf8m zv :ential throughout?

A satellite orbits the Earth ag- eyw dwy-g72long a gravitational equipotential line. What shape must the 7-2ygw- dweyg orbit be?

When dealing with practical devices, w/nz5 zu2z2b,nf uok9w (3rthq e often take the ground (the Earth) to be 0 V. If, instead, we said the ground was how would this affect (a) the potential V, and (b) the elk zu fn/25nozh(qbw32turz9, ectric field E, at other points?

When a battery is connecthc,l97 .( -j9 m ywr.shvfnotted to a capacitor, why do the two plates acquire charges of the same ma.(, r9-9l 7hnmsj.vtoh cywf tgnitude? Will this be true if the two conductors are different sizes or shapes?

We have seen that the6 up7wfygod9: capacitance C depends on the size, shape, and position of the two conductors, as well as on the dielefpuodgwy6 7:9 ctric constant K. What then did we mean when we said that C is a constant in Eq. 17 – 7?

  How much work does the electric field do i mm*d/xcm7 wa,n 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 in moving a /lp7.m4iegt eproton from a point with a potential op.t i7e l4me/gf $+125V$ 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 electrbemw 0t-h059 4gibw byon gain (in joules and eV) if it accelerates through a9bh iw-bbm5g04 wt y0e potential difference of 23,000 V in a TV picture tube?
   $ \times10^{-15 }\,J$
   eV

  An electron acquires +dm igab, n,;7)it m-nh. xhua$7.45 \times10^{ -16}\,J$ 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*q/ mnx9u m;1n*juy( oj7wrpw between two parallel plates 5.8 mm apart if the potential difference betwrwo 1/jjyw9p*mm ux(n nu; q7*een them is 220 V?    $ \times10^{ 4}\,V/m$

  An electric field ofzsv5x7 /3 ivl9m2kozx $640V/m$ is desired between two parallel plates 11.0 mm apart. How large a voltage should be applied?    V

  The electric field between two parallel plates connected to a 45-V bat( 5gof zsjz6+otery is $1500V/m$ How far apart are the plates?    m

  The electric field between two parallel plates con(g lo/8m auu(9 i0ujovnected to a 45-V battery is $1500V/m$ How far apart are the plates?    m

  What potential difference is neelzy:yz0 : q jyu*9z )al6k4iraded to give a helium nucleus $(Q=2e)$ 65.0 keV of kinetic energy?    $ \times10^{4 }\,V$

  Two parallel plates, connected to a 200-V power supply, are separated qh dly4+tu,sw :f-we0 by an air gap. How small can the gap be wlstw d,f hyu4+e:-0q if the air is not to become conducting by exceeding its breakdown value of $E\,=3 \times10^{ 6}\,V/m$?   $ \times10^{-5 }\,m$

  The work done by an external fmd:d4* vdgg2q1gxqow uc(t(*orce to move 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 electro-6 icdj y1 lp9.z;g:k lqnrq-xn2w cb2n with kinetic energy
(a) 750-eV,    $ \times10^{7 }\;m/s$
(b) 3.2-keV?    $ \times10^{7 }\;m/s$

  What is the speed of a proton whose kinetic energy is 3.2 keV? s-(mhf,sou(u rj -d9d    $ \times10^{5}\,m/s$

  An alpha particle (which is a helium nurjbpyc w18 ))s8g s- zn6x)jbfcleus, $Q=+2e$, $m\,=\,6.64\times10^{-27 }\,kg$) is emitted in a radioactive decay with $_{KE}$ = $5.53MeV$ What is its speed?    $ \times10^{7}\,m/s$

  What is the electric potential 15.pp.h q1-y8 e* ayk)pd( by4scf0 cm from a $4.00\mu C$ point charge?    $ \times10^{ 5}\,V$

  A point charge Q creates an electrdi 6viyi+ 5o+m )z1afpz 5dmyod3;:gfic 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 the shape of ny-hy9hhd 6 -hzp 8 y2;wdm su* oo9*kz/gwpk5a football. This conductor carries a net negative charouy dph6n ;**5ydhykkw89zhgs2 o -w /mzh p-9ge, $-Q$. Draw in a dozen electric field lines and two equipotential lines.

  (a) What is the electric potentm5ub7d *xwlbk0 8cirwc8* *vks fg8s (ial 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 arranged at the cuol7bz+jh58p e 6vqry;+okc0 orners of a square of side L as shown in Fig. 17–25.jz6 8p+eb75 ov; r+o0yhcklqu What is the potential at the fourth corner (point A), taking $V\,=\,0$ at a great distance?

  An electron starts from rest 3ue l 1u8wic 2j+k0xc/j2.5 cm from a fixed point charge 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 elect7hcz.e l1i:dp 68 ujh uytn4w;rons from a great distance apart tohwu :;phitdu7l1 zej. 86n yc4 $1.0 \times10^{-10 }\,m$ from one another (at the corners of an equilateral triangle)?    $ \times10^{-18 }\,J$

  Consider point a which is 72njq 9rz,+4v*sgw5b +q8 s rlna cm north 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 must be usl oz;jkb q-or:s-ioi :g+hr;ago:n7 8ed 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 opposite charges are separated by a distance +kap5j it dg h89c+jxqn,q*b9d, as shown in Fig. 17–27. Determine a formul +dhxct 5 *k,q9+9 gbp8qajjnia for $V_{BA}\,=\,V_B-V_A$ for points B and A on the line between the charges.

  In the Bohr model of the hydrov..af omnd(s 1gen atom, an electron orbits a proton (the nucleus) in a m1fv. (sdo .ancircular 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 proto*l9* rb (a8pz,nlcz,dsm1rkyv xru21n are $ 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 w ijf2a6mi );y x;h1fnvhose dipole 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 theqq,wm mgu99c) negative to the positive charge. The water molecule, Fig. 17–28, has a dipole moment which can be considered as the vector sum of the two dipole ,ugm9c wq)mq9moments, $\vec{P}_1$ 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 capacit3nw, 7if;0 w1hljofudor 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$

  The two plates of a capacitor hoe3 i rqbd.do4oh n96uijcn;-;ld $+2500\mu C$ 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 minus cha;iw4ctorx 5q ,je2f1ml3b0 a yrges of $ 16.5\times10^{-8 }\,C$. What is the voltage across the capacitor?    V

  The potential difference between two short sections of parallel wire in aktw x7jsrd-yhv/;w, mt(w 6d q- (rsy;ir is 120 V. They carry equal and opposite charge of magnitude 95 pC. Whq k;x(hyrrt s/m6 ;( 7djywwdt-,vw- sat is the capacitance of the two wires?    $ \times10^{13 }\,F$

  How much charge flows from eachol +u2vgw/7wtc43e tw terminal of a 12.0-V battery when it is connected +olcw3u 4 2g7e w/ttvwto a $7.00-\mu F$ capacitor?    $ \times10^{-5 }\,C$

  A 0.20-F capacitor is desired. What area must the plates have if cvou*r1 43lslthey are to be separated by a 2.2-o4 lvlr1cs*3umm air gap?    $ \times10^{ 7}\,m^2$

  The charge on a capacdkb*mj,mg ;*j59eifu7 a 9l hsitor increases 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 of )xxnth 8 fr5t-$8.5 \times10^{ 5}\,V/m$ 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 opposi6 j 2cgxko2f1cte $5.2\mu C$ 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 electmlk-lmb9 *pvfj84ih .ric field between 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. 17–29, uc03w;3wy de8:xthzbp2l1z fqj, mn a) and then is disconnected from m1e3, lqu 8fyn;z0hp 2j,zx dbtwc3:wthe battery. When this 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 pl9e9e mpagr7+t orf2h)ates 5.5 cm on a side that are separated by 1.8 mm of pap 2f9e7orh re9ma g)+traffin?    $ \times10^{-11 }\,F$

  What is the capacitance of a pair of circular plates with a radius of 5 w*.m, pl)wvc13ldw yfn ro4h*.0 cm separated by 3.2 mm of ,pfw w d*hmv*1 c4o)w.lny3rlmica?    $ \times10^{-10 }\,F$

  A 3500-pF air-gap capacitor is connected to a 22-V battery. If a piece of m-1qp 9dqfkb(a1z+xqfica is placed betweenfq1d bzaq(x-k 9+f 1pq the plates, how much charge will flow from the battery?    $ \times10^{ -7}\,C$

  The electric field between the plates of a paper-s7qmo 0/ax xzr/eparated $(K=3.75)$ 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 capacitor. How muc 1qwuh1+rzta ,h *vu-eh energy is stored?    $ \times10^{-4 }\,J$

  A cardiac defibrillator is used to shock a hearte - jnm*ax2rl76 ql;3xgd/yg a that is beating erratically. A capacitor in this device is charged to 5.0 kV and stores xne*;3laajr m2ydx gg7q l/6-1200 J of energy. What is its capacitance?    $ \times10^{-5 }\,F$

  How much energy is stored by the electric field v*y2oc4 ws o/pbetween two square plates, 8.0 cm on a side, separated by a 1.5-mm a*py2sc4 /oowv ir gap? The charges on the plates are equal and opposite and of magnitude $420\mu C$.    J

  A homemade capacitor is assembled by placing two 9-in. pie pans 5 cm apa*eap7r r( bfuawhv 03(-ghrs5 rt and connecting them to the opposite wv re rh*(up r0fga3b7h-5(saterminals 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 hasyimr05 y7-y xd fixed 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 capacitor change if (a) thezpq* 1g-2dp8c ry4f)wyjoo- n c.zu x5 potential difference is doubled, and (b) the charge on each plate is doubled, as the capacc* 21dzcj - pz - xognpu58.)fqryy4owitor 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 xz3 7sb2hla2rhorizontally by 7.0 kV. They then pass through a uniform electric 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 cen 3xbarslz272h ter. Estimate the value of E.    $ \times10^{5 }\,V/m$

  Electrons are accelerated by 6.0 kV in a CRT. The sl(+usw s.( vnammp2k;creen is 30 cm wide and is 34 cm from the 2.6-cm-long deflection plates. O + .wmskp((;vum2sl naver 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 frd yv6*8z6ed2vyhy y(h om point A to point B(hyv2d8edy yzh*6y6 v.
(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 transfers 4.0 C of charge and 4.2 MJ of energy to t gcqnvz0,kq 2/he 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’bd1rm) j3kqzdwnh 6* .s surface whose magnitude is 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, elealh2(chlgy9 : ctrons are accelerated 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 fo2galhyc 9 h(l:rce 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 f(yy v/eyqg :t .k:s7dnpj-8 5wfxqpd+rom 21$^{\circ}\,C$ to 95$^{\circ}\,C$. What is the potential difference across the plates?    V

  An uncharged capacitor is connecttqg;q *qe4 j5ied to a 24.0-V battery until it is fully charged, after which it is q5itgqq;*4 jedisconnected from the battery. A slab of paraffin is then inserted between the plates. What will now be the voltage between the plates?    V

  Dry air will break dovqh.g qnzu4 z/qus 4()wn if the electric field 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 equilateral triangle (side cn+cfd* +l/yeL) as shown in Fig. 17–30. Determine dce*/ylnf++c the potential at the midpoint of each of the sides.

  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 ikai1vzv+1g;r og9p8j q 5+mda piece of Pyrex glass is placed between the plates, hoapdiv1gjrv5mz9 1+k; 8 iq og+w much charge will then flow from the battery?    $ \times10^{-8 }\,C$

  An electron is accelerated horizontally from ress2z )1 ;jqydgct in a television picture tube by a potential difference of 5500 V. It then passes between two horizontal plates 6.5 cm long and 1j 2s)dz gc;qy1.3 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 capacitance y 41qz6hk3tou7ih i5u $C_1$ 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-fil1x py6b/f us9ndz(x :tled parallel-plate capacitor for a circuit you are building. To make it a reasonable siz6: 9dp/(yx1fbnutx s ze, 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 Earth there is an z+8o5/dmzzvfi 2n z 6kelectric 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 3kfdwwzfei hg 8 5dr+10, 8 aykjw3j,aa pulsed nitrogen laser 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, the potential difference between the Eart j)wf8rfqo65dad/to8h and the bottom of the thunderclouds can be as high as 35,000,000 V. The bottoms of the thunderclouds are typically 1500 m above the jawf)/rf o8dd5o68q t 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 eno z.2xqusgj4b cm4j r-+f2f5 go(dj m-yugh energy to some electrons 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 is kept at a negative enough potential that the emitted electrons are slowed down and stopped, and return to the barium sur24quc s. jmdyfmf- -g 4o5(jr j2xgz+bface. 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 placed qk p s+vzl31p136 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 0.1qv(uzq ij3o ;65-mm-thick piece ojqui6 (;oq3vz f 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 capaciwg/d*kqrrp gqk 8*abooyy.d ;n9iv :hry4 -5; tor with 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(i;d5*gxv j vu from each other. Their charges are $Q_1$=$Q_2$=$5.0\mu C$, 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 as shown n :go:sx-kh +b.vjos :l1gow, 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$