GCu s 1:0.2Hin nay urani t nhin cha hai ng v phng x235Uv238U, vi t l s ht235Uv s ht238Ul71000. Bit chu k bn r ca235Uv238Uln lt l7,00.108nm v4,50.109nm. Cch y bao nhiu nm, urani t nhin c t l s ht235Uv s ht238Ul3100?3,15t nm.

1,74t nm.

2,22t nm.

2,74t nm.

Cu s 2:Chiu mt tia sng n sc t khng kh (chit sut bng1) vo mt phng ca mt khi thy tinh vi gc ti60o. Nu tia phn x v tia khc x vung gc vi nhau th chit sut ca loi thy tinh ny bng3.

32.

2.

23.

Cu s 3:Cho hai dao ng iu ha cng phng c cc phng trnh ln lt lx1=4cos(t6)(cm) vx2=4cos(t2)(cm). Dao ng tng hp ca hai dao ng ny c bin l42cm

2cm

43cm

8cm

Cu s 4:Mt vt dao ng cng bc di tc dng ca mt ngoi lc bin thin iu ha vi tn sf. Chu k dao ng ca vt l

12f.

2f.

2f.

1f.

Cu s 5:nh sng c tn s ln nht trong s cc nh sng n sc: , lam, chm, tm l nh sngchm.

lam.

.

tm.

Cu s 6:Vt nh ca mt con lc l xo dao ng iu ha theo phng ngang, mc th nng ti v tr cn bng. Khi gia tc ca vt c ln bng mt na ln gia tc cc i th t s gia ng nng v th nng ca vt l12.

3

2

13.

Cu s 7:Mch dao ng in t LC l tng ang hot ng. in tch ca mt bn t inbin thin theo hm bc nht ca thi gian.

khng thay i theo thi gian.

bin thin theo hm bc hai ca thi gian.

bin thin iu ha theo thi gian.

Cu s 8:in nng c truyn t ni pht n mt khu dn c bng ng dy mt pha vi hiu sut truyn ti l 90\%. Coi hao ph in nng ch do ta nhit trn ng dy v khng vt qu 20\% . Nu cng sut s dng in ca khu dn c ny tng 20\% v gi nguyn in p ni pht th hiu sut truyn ti in nng trn chnh ng dy l89,2%.

92,8%.

87,7%.

85,8%.

Cu s 9:Thin th khng phi l hnh tinh trong h Mt Tri lMc tinh.

Mt Trng.

Kim tinh.

Tri t.

Cu s 10:t hiu in thu=U2sint(viUvkhng i) vo hai u mt on mch RLC khng phn nhnh, xc nh. Dng in chy trong mch cgi tr tc thi ph thuc vo thi gian theo quy lut ca hm s sin hoc cosin.

gi tr tc thi thay i cn chiu khng thay i theo thi gian.

chiu thay i nhng gi tr tc thi khng thay i theo thi gian.

cng hiu dng thay i theo thi gian.

Cu s 11:Mt mch dao ng in t l tng ang c dao ng in t t do. Bit in tch cc i trn mt bn t in l42Cv cng dng in cc i trong mch l0,52A. Thi gian ngn nht in tch trn mt bn t gim t gi tr cc i n na gi tr cc i l83s.

43s.

23s.

163s.

Cu s 12:t n pu=U0cos(100t6)(V) vo hai u on mch cR,L,Cmc ni tip th cng dng in qua mch li=I0cos(100t+6)(A). H s cng sut ca on mch bng0,50.

0,86.

1,00.

0,71.

Cu s 13:Con lc l xo gm vt nh khi lng100g gn vi mt l xo nh. Con lc dao ng iu ha theo phng ngang vi phng trnhx=10cos10t(cm). Mc th nng v tr cn bng. Ly2=10. C nng ca con lc bng1,00J.

0,10J.

0,50J.

0,05J.

Cu s 14:Pht biu no sau y sai?Trong chn khng, mi nh sng n sc c mt bc sng xc nh

Trong chn khng, bc sng ca nh sng nh hn bc sng ca nh sng tm.

Trong nh sng trng c v s nh sng n sc.

Trong chn khng, cc nh sng n sc khc nhau truyn vi cng tc .

Cu s 15:Trong gi hc thc hnh, hc sinh mc ni tip mt qut in xoay chiu vi in trRri mc hai u on mch ny vo in p xoay chiu c gi tr hiu dng380V. Bit qut in ny c cc gi tr nh mc:220V 88W v khi hot ng ng cng sut nh mc th lch pha gia in p hai u qut v cng dng in qua n l, vicos=0,8. qut in ny chy ng cng sut nh mc thRbng354.

361.

267.

180.

Cu s 16:Hin tng phn x ton phn c th xy ra khi nh sng truyn theo chiu tkhng kh vo nc .

khng kh vo thy tinh.

nc vo khng kh.

nc vo khng kh.

Cu s 17:Quang in tr c ch to tcht bn dn v c c im l dn in km khi khng b chiu sng v tr nn dn in tt khi c chiu sng thch hp.

cht bn dn v c c im l dn in tt khi khng b chiu sng v tr nn dn in km khi c chiu sng thch hp.

kim loi v c c im l in tr sut ca n gim khi c nh sng thch hp chiu vo.

kim loi v c c im l in tr sut ca n tng khi c nh sng thch hp chiu vo.

Cu s 18:Mt mch dao ng in t LC l tng gm cun cm thun c t cm5Hv t in c in dung5F. Trong mch c dao ng in t t do. Khang thi gian gia hai ln lin tip m in tch trn mt bn t in c ln cc i l:2,5.106s.

10.106s.

5.106s.

106s.

Cu s 19:TiaXc cng bn cht vitia+.

tia.

tia.

tia hng ngai .

Cu s 20:Biu thc tnh chu k dao ng iu ha ca con lc vt l lT=2Imgd; trong :Il momen qun tnh ca con lc i vi trc quay nm ngang c nh xuyn qua vt,mvgln lt l khi lng ca con lc v gia tc trng trng ti ni t con lc. i lngdtrong biu thc lchiu di ln nht ca vt dng lm con lc.

khi lng ring ca vt dng lm con lc.

khong cch t trng tm ca con lc n trc quay.

khong cch t trng tm ca con lc n ng thng ng qua trc quay.

Cu s 21:mt vt sng nh vung gc vi trc chnh ca thu knh, cch thu knh15cm. Thu knh cho mt nh o ln gp hai ln vt. Tiu c ca thu knh l30cm.

20cm.

30cm.

10cm.

Cu s 22:Ti mt ni xc nh, chu k dao ng iu ha ca con lc t l thun vicn bc hai chiu di con lc

chiu di con lc

cn bc hai gia tc trng trng

gia tc trng trng

Cu s 23:Mch dao ng in t gm cun cm thun c t cm1mH v t in c in dung4nF. Tn s dao ng ring ca mch l2,5.105Hz.

5.105Hz.

2,5.106Hz.

5.106Hz.

Cu s 24:Mt ngi mt khng c tt quan st mt vt qua mt knh hin vi quang hc trong trng thi mt khng iu tit. Mt ngi c im cc cn cch mt25cm. Th knh c tiu c4cm v vt cch vt knh1312cm . Khi bi gic ca knh hin vi bng75. Tiu c vt knhf1v di quang hcca knh hin vi ny lf1=1,2cm v=16cm.

f1=1cm v=12cm.

f1=0,5cm v=11cm.

f1=0,8cm v=14cm.

Cu s 25:Khi so snh ht nhn126Cv ht nhn146C, pht biu no sau y ng?in tch ca ht nhn126Cnh hn in tch ca ht nhn146C.

S nucln ca ht nhn126Cbng s nucln ca ht nhn146C.

S prtn ca ht nhn126Cln hn s prtn ca ht nhn146C.

S ntron ca ht nhn126Cnh hn s ntron ca ht nhn146C.

Cu s 26:Nguyn t hiro ang trng thi c bn c mc nng lng bng13,6eV. chuyn ln trng thi dng c mc nng lng3,4eV th nguyn t hiro phi hp th mt photon c nng lng17eV.

10,2eV.

4eV.

10,2eV.

Cu s 27:Mt vt nh dao ng iu ha dc theo trc Ox vi bin 5cm, chu k2s. Ti thi imt=0vt i qua v tr cn bng Ox theo chiu dng. Phng trnh dao ng ca vt lx=5cos(t2)(cm).

x=5cos(t+2)(cm).

x=5cos(2t+2)(cm).

x=5cos(2t2)(cm).

Cu s 28:Chiu mt chm tia sng n sc, song song, hp (coi nh mt tia sng) t khng kh vo thu tinh vi gc tii. Bit tia khc x trong thu tinh vung gc vi tia phn x ngoi khng kh, chit sut t i ca thu tinh i vi khng kh bng3. Gc tiic gi tr l750.

450.

300.

600.

Cu s 29:Khi chiu ln lt hai bc x c tn s lf1,f2(vif1