Victory for the ACT Student Text 15e

410 • C AMBRIDGE P RACTICE T EST R EINFORCEMENT

PASSAGE IV Š‡ ”‡•‹•–ƒ…‡ ȋ R ‹ ‘ŠǦ‡–‡”•Ȍ ‘ˆ –Š‡ ƒ–‡”‹ƒŽǤ Š‡ ˜‘Ž–ƒ‰‡ ȋ V –Š‡ ”‡•‹•–ƒ…‡ ƒ† –Š‡…—””‡– ȋ I ˆ‘ŽŽ‘™‹‰ ˆ‘”—Žƒǣ = + + + … ‡•‹•–‘”• ‹ ’ƒ”ƒŽŽ‡Ž ƒ…– ƒ• ‘‡ ”‡•‹•–‘” ƒ……‘”†‹‰ –‘ –Š‡ ˆ‘ŽŽ‘™‹‰ ˆ‘”—Žƒǣ … Š‡ ”‡•‹•–‹˜‹–‹‡• ‘ˆ •‡˜‡”ƒŽ ƒ–‡”‹ƒŽ• ƒ– ʹͲ ᤪ ƒ”‡ Ž‹•–‡† ‹ ƒ„Ž‡ ͳǤ Table 1 R R R R s 1 2 3 R R R R 1 1 1 1 p 1 2 3 = + + +

ǡ ‡ƒ•—”‡† ‹ ‘Š•Ȍ ‘ˆ ƒ ƒ–‡”‹ƒŽ ‹• †‹”‡…–Ž› ’”‘’‘”–‹‘ƒŽ ȋ v

Ȍ –‘ –Š‡ ”‡•‹•–‹˜‹–› ȋ r ǡ ‡ƒ•—”‡† ‹ ˜‘Ž–•Ȍ ‹ ƒ…‹”…—‹– ‹• †‹”‡…–Ž› ’”‘’‘”–‹‘ƒŽ –‘ „‘–Š ǡ ‡ƒ•—”‡† ‹ ƒ’‡”‡•ȌǤ ‡•‹•–‘”• ‹ •‡”‹‡• ƒ…– ƒ• ‘‡ ”‡•‹•–‘” ƒ……‘”†‹‰ –‘ –Š‡ ǡ ‡ƒ•—”‡†

Substance Resistivity, r (ohm-meters) Ž—‹— .2 63 10 8 # Copper .1 72 10 8 # ‡”ƒ‹— .6 00 10 1 # ‹Ž‹…‘ .2 30 10 3 # ‹Ž˜‡” .1 47 10 8 # —Žˆ—” .1 00 10 15 #

17. ……‘”†‹‰ –‘ –Š‡ ‹ˆ‘”ƒ–‹‘ ’”‘˜‹†‡†ǡ –Š‡ „‡•– ˆ‘”—Žƒ ˆ‘” –Š‡ ˜‘Ž–ƒ‰‡ ‹ ƒ…‹”…—‹–ǡ ™Š‡”‡ ˜‘Ž–ƒ‰‡ ‹• V ǡ…—””‡– ‹• I ǡ ƒ† ”‡•‹•–ƒ…‡ ‹• R ǡ ‹•ǣ Ǥ V R I ? 18. ™‘ ”‡•‹•–‘”• ™‹–Š ƒ ”‡•‹•–ƒ…‡ ‘ˆ ʹ ‘Š• ‡ƒ…Š ƒ”‡ ’Žƒ…‡† ‹ •‡”‹‡•Ǥ ‘™ †‘‡• –Š‡ ˜‘Ž–ƒ‰‡ ‹ –Š‡ …‹”…—‹–…‘’ƒ”‡ ™‹–Š –Š‡ ˜‘Ž–ƒ‰‡ ‹ ƒ…‹”…—‹– ™‹–Š ‘Ž› ‘‡ ”‡•‹•–‘”ǡ ™‹–Š ƒ ”‡•‹•–ƒ…‡ ‘ˆ ʹ ‘Š•ǫ ȋ ••—‡…—””‡– ”‡ƒ‹•…‘•–ƒ–ǤȌ Ǥ Š‡ ˜‘Ž–ƒ‰‡ ‹• †‘—„Ž‡†Ǥ Ǥ Š‡ ˜‘Ž–ƒ‰‡ ‹• ŠƒŽ˜‡†Ǥ Ǥ Š‡ ˜‘Ž–ƒ‰‡ ‹• –Š‡ •ƒ‡Ǥ Ǥ Š‡ ˜‘Ž–ƒ‰‡ ‹• œ‡”‘Ǥ Ǥ Ǥ V I R ? Ǥ Ǥ V IR ? Ǥ Ǥ V I R ? Ǥ

19. ……‘”†‹‰ –‘ –Š‡ ‹ˆ‘”ƒ–‹‘ ’”‘˜‹†‡†ǡ Š‘™ ™‘—Ž† –Š‡ ˜‘Ž–ƒ‰‡ ‹ ƒ…‹”…—‹– ™‹–Š ƒ •‹Ž˜‡” ”‡•‹•–‘”…‘’ƒ”‡ –‘ –Š‡ ˜‘Ž–ƒ‰‡ ‹ ƒ…‹”…—‹– ™‹–Š ƒ ‰‡”ƒ‹— ”‡•‹•–‘” ‘ˆ –Š‡ •ƒ‡ Ž‡‰–Šǫ ȋ —””‡– ‹• –Š‡ •ƒ‡ ‹ „‘–Š…‹”…—‹–•ǤȌ Ǥ Š‡ ˜‘Ž–ƒ‰‡ ‹ –Š‡ ‰‡”ƒ‹—…‹”…—‹– ™‘—Ž† „‡ ‰”‡ƒ–‡”Ǥ Ǥ Š‡ ˜‘Ž–ƒ‰‡ ‹ –Š‡ •‹Ž˜‡”…‹”…—‹– ™‘—Ž† „‡ ‰”‡ƒ–‡”Ǥ Ǥ Š‡ ˜‘Ž–ƒ‰‡ ™‘—Ž† „‡ –Š‡ •ƒ‡ ‹ „‘–Š …‹”…—‹–•Ǥ Ǥ ƒ‘– „‡ †‡–‡”‹‡† ˆ”‘ –Š‡ ‰‹˜‡ ‹ˆ‘”ƒ–‹‘

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