95.26: Two positive point charges repe0et7es fdrno:u 5 aw6fj7if2 ez0(i)z qo/vq*l each other with force 0.36 N when their separation isiq5/o j2v)fzfue t7 s7z*iee0n afqr 6od(:w 0 1.5 m. What force do they exert on each other when their separation is 1.0 m?

  12.13 Approximately how many electrons must be removed fromp4 r,e; ch/i x2s;svto an electrically neutral object to give it a net charge of Q = + 1.00 Co /ith 42cx;pvses; ,r ?

  13.15 In a circuit, the flo1u :/xo788tj(oae wxnfzl (z -vcca4s w of electrons in a horizontal wire produces a constant current of 3.20 A for a vu7oalez1jo c8 /-8(:zn(tcasxf4 x w time of 3.0 hour. Which one of the following choices best represents the number of electrons that pass through a vertical cross-section of the wire during this time?

  13.07: Two identical particles are fixed in pla1ev7l .wbjmz0ce a distance of 0.50mapart. The electric force that one particle exerts on the other has a magnitude of 3.00 N. Which one of the fol zvmwjlb.e7 01lowing choices best represents the magnitude of each particle’s charge?

  07.25: If two protons are spaced by a distance R, what is the ratio of/twl o5gp5f f-ow i/c8 the gravitatitl cwfoo/pg/8-i wf55onal force that one
proton exerts on the other to the electric force that one proton exerts on the other?That is,$\frac{F_{gravity}}{F_{electric}}$=

  10.12: A scientist sets up an experiment with a proton of charge Q anqy+ ,g0d qqmt.d mass M being placed near a helium nucleus (2 protons and 2 neutrons) of charge +2Q and mdyqq,t mq0g.+ ass 4M. The objects are each released from rest and begin to move. From the scientist’s point of view, which choice best describes the object that experiences the greatest magnitude of electric force from the other and which object experiences the greatest magnitude of acceleration? Ignore gravity.

  94.39: A small object with charge q and weight mg is attached to one end o 9dr;7et5 bkb +dhbw by.:lh/n./m4(i z gezqwf a string of length L. The other end is attached to a stationary support. The sysd..y w gzzb7m/ /e(klbw+e5br9bnidq 4t;hh:tem is placed in a uniform horizontal electric field E, as shown in the accompanying figure. In the presence of the field, the string makes a constant angle q with the vertical. What is the sign and magnitude of q?

  09.38: A small object of mass M and charge Q is connected to an insuo v1g (gw3fdv 34ps3dtlating massless string in a vacuum on Earth. A uniform electric field exists throughout the region of the vacuum as indicated. The mass remains in static equilibrium at an angle of θ with the vertical as shown in the figure. When the string is cut, which of the illustrated paths best indicates the trajectory of the m4 1g fdv w3dp33tosvg(ass?

  13.29 Two electrons enter a reknw.r 6c7cmq skscl0+-u3t c0 gion between charged capacitor plates with equal speed v. Electron A is diq3cn0m7kss cw 60crl.ku ct-+ rected horizontally to the left while electron B is directed at$30^{\circ}$below the horizontal. Each electron makes it to the left-hand plate. Which one of the following choices best compares the speeds of the charges ( $V_A$, $V_B$) upon arrival at the left plate? Consider only the electrons A and B’s interactions with the constant electric field between the plates, ignoring any relativistic effects.

  08.06: A positive poif,4;0gphsl0: n tgrc6 mxhlh (rht+ r5nt charge exerts a force of magnitude F on a negative point charge placed a distance x away. If the distance between the two point charges is halved, what is the magnitude of the new force t :h0+t;ltgpf l5hsh0,r r crgmh( x64nhat the positive point charge exerts on the negative point charge?

  98.08: When two charged point-li a8m-foui3b6;vj0s iike objects are separated by a distance R, the force between them is F. If the distance between them is quadrupled, t i86f30v omi absij;-uhe force between them is

  03.18: Two identical electrical point charges Q, separated by a dist0w f*qkrn pd5l+r6+mgance produce an electrical force ofF on one another. If the distance+w0nrkg*5l6fd +mrq p is decreased to a distance of 0.40, what is the strength of
the resulting force?

  96.34: A point charge +q is placed midway between two :0kcbp,ylnw yv;o,3i 1.ra pn point charges +3q and -q separated by a distance 2d. If Coulomb’s constant is k, the magni y ib 0c ;1ywkp:3nlrap.n,vo,tude of the force on the charge +q is:

  01.31: A positive point charge of +q and a negative point charge of -q a*)3fme rp8a 7jt c*fqo ,8smwere separated by a distance d. What wouctp8re3,7 )o8*meqfmfasw*jld be the magnitude of the electric field midway between the two charges?

  08.33: Two point charge4rf,swcy 6,bcs are fixed on the x-axis inotherwise empty space as shown belo 6y,4,cw fcbsrw.
In which Region(s) is there a place on the x-axis (aside from infinity) at which the electric potential is equal to zero?

  08.34: Two point charges are fixed on the x-axis in otherwise epfp 5z/la2+p empty space as shown beze flap+ /2p5plow.
In which Region(s) is there a place on the x-axis (aside from infinity) at which the electric field is equal to zero?

  98.23: Two charges +Q and –4Q are arranged as shges)i bf; bv:0own in the accompanying diagram. At which of the labeled points ibgs ;ifbe0) :vs the field most nearly zero?

  98.30: Four positive point charges are arranged as shown in the accompanying di*p mhqte :40ond: 7eleagram. The force between charges 1 and 3 is 6.0 N; the force between charges 2 and 3 is 5.q0de4eo:hn :tpl me7*0 N; and the force between charges 3 and 4 is 3.0 N. The magnitude of the total force on charge 3 is most nearly

  94.08: A point chargm1 2sioa 1r 8d9qzrs0ye of +4.0 μC is placed on the negative x-axis 0.20 m to the left of the origin, as shown in the accompanying figure. A second point charge q is placed on themzsr1q1o2 yisd8a9 r0 positive x-axis 0.30 mto the right of the origin. The net electric field at the origin is zero. What is q?

  95.36: Assume the electric potential is zero at infinitywsa0y79 ny2;mhvfv n9. A point charge of +4.0μC is placed on the negative x-axis 0.20 m to the left of the origin, as shown in the accompanying figure. A second point charge q is placed on the positive x-axis 0.30 m to th;n ahy 9 nv02w9y7mfsve right of the origin. The net electric potential at the origin is also zero. What is q’s charge?

  03.27: Four electrical charges are arranged on the corners of a 10 cm sh7z1b 3 agyr;kquare as shown. What37zgyra;b 1hk would be the direction of the resulting electric
field at the center point P?

  14.10: Two charges −Q and +Q, are fixeqcn;mxo ym6p)xex9w+i ) ah z, 2-,ihmd in place on the x-axis, each a distance a from the origin as shown. At the point labeled P, a distance along they-axis from the origin, what is the direction of the eqm 2 xep+hxo),-m)iiyzc w,6namh;x9 lectric field from the given charges?

  16.33 Given the configuration of three charges, +Q, +Q, and −2Q, x-nt)+xbmi i/w mb76vwhich one of the following choices best represents the direction of the electric field at the point P and the sign of vi) m6 iwtbm xb+x7/-nthe electric potential at P from these charges?

  17.43: A semi-circle has radius R )imo96po/dna , total charge Q, and a charge per unit length 6/a mopnd9)oi given as $λ=λ_0cosθ$ with θ defined in the figure and $λ_0$ a positive constant. Which one of the following choices gives the electric field strength at the point labeled P?