8 Piv txwv ntawm cov lus nug txog daim iav concave
1. Daim duab pleev xim kom raug ntawm daim iav concave pom muaj nyob rau hauv...
Kev Sib Tham
Daim duab tseeb ntawm daim iav concave yog nyob rau hauv cov lus teb B. Yuav kom koj nkag siab meej, ua tib zoo mloog cov lus piav qhia hauv qab no.
Yog tias qhov deb ntawm yam khoom me dua qhov ntev ntawm lub iav concave, qhov kev tsim duab yuav tshwm sim raws li pom hauv daim duab hauv qab no.
Yog tias cov khoom nyob nruab nrab ntawm qhov chaw tsom mus rau qhov chaw thiab qhov chaw nruab nrab ntawm qhov nkhaus ntawm daim iav concave, cov duab tsim zoo li daim duab hauv qab no.
Yog tias qhov deb ntawm cov khoom loj dua li lub vojvoog ntawm qhov nkhaus (R) ntawm daim iav concave, daim duab tsim yuav tshwm sim zoo li hauv daim duab hauv qab no.
Cov lus teb yog B.
2. Daim duab qhia tseeb ntawm kev tsim ib daim duab ntawm ib yam khoom nyob rau pem hauv ntej ntawm daim iav concave yog qhia nyob rau hauv daim duab...
Kev Sib Tham
Yog tias qhov deb ntawm yam khoom me dua qhov ntev ntawm lub iav concave, qhov kev tsim duab yuav tshwm sim raws li pom hauv daim duab hauv qab no.
Yog tias cov khoom nyob nruab nrab ntawm qhov chaw tsom mus rau qhov chaw thiab qhov chaw nruab nrab ntawm qhov nkhaus ntawm daim iav concave, cov duab tsim zoo li daim duab hauv qab no.
Yog tias qhov deb ntawm cov khoom loj dua li lub vojvoog ntawm qhov nkhaus (R) ntawm daim iav concave, daim duab tsim yuav tshwm sim zoo li hauv daim duab hauv qab no.
Cov lus teb A tsis yog lawm vim tias lub teeb uas cuam tshuam tsis tuaj yeem hla dhau qhov chaw nruab nrab ntawm daim iav qhov nkhaus (M).
Cov lus teb B tsis yog lawm vim tias lub teeb uas cuam tshuam tsis sib tshuam rau ntawm qhov kawg ntawm yam khoom.
Cov lus teb C tsis yog lawm vim tias lub teeb uas cuam tshuam tsis sib tshuam rau ntawm qhov kawg ntawm yam khoom.
Cov lus teb yog D.
3. Daim duab tseeb ntawm cov teeb ci tshwj xeeb ntawm daim iav concave hauv qab no yog...
Kev Sib Tham
Qhov xwm txheej lossis txoj kab uas cuam tshuam yuav tsum hla dhau qhov chaw tsom mus rau.
Cov lus teb yog B.
5. Saib daim duab ntawm daim iav concave hauv qab no!
Qhov xwm txheej ntawm daim duab uas tsim los ntawm daim iav yog ...
A. tiag tiag, txo qis thiab ncaj nraim
B. tiag tiag, loj dua thiab ncaj nraim
C. tiag tiag, txo qis thiab tig rov qab
D. tiag tiag, nthuav dav thiab tig rov qab
Kev Sib Tham
Qhov xwm txheej ntawm daim duab ntxoov ntxoo yog qhov tseeb, txo qis thiab tig rov qab.
Cov lus teb yog C.
5. Muab ib yam khoom uas siab 1 cm tso rau ntawm daim iav uas muaj qhov ntev focal ntev li 15 cm deb li 10 cm. Txheeb xyuas seb:
A. Qhov deb ntawm tus duab ntxoov ntxoo?
B. Tus duab ntxoov ntxoo siab npaum li cas?
C. Cov yam ntxwv ntawm cov duab ntxoov ntxoo yog dab tsi?
Kev Sib Tham
Nws paub tias:
Qhov siab ntawm yam khoom (h) = 1 cm
Qhov nrug ntawm yam khoom (s) = 10 cm
Qhov ntev ntawm daim iav concave (f) = 15 cm
Lus teb:
A. Qhov deb ntawm daim duab (s')
1/f = 1/s + 1/s'
1/s' = 1/f – 1/s = 1/15 – 1/10 = 2/30 – 3/30 = -1/30
s' = -30/1 = -30 cm
Lub cim tsis zoo rau qhov nrug ntawm duab ntxoov ntxoo txhais tau tias lub duab ntxoov ntxoo yog virtual.
B. Qhov siab ntawm qhov ntxoov ntxoo (h')
Ua ntej xam qhov siab ntawm daim duab ntxoov ntxoo, xub xam qhov loj ntawm daim duab ntxoov ntxoo.
Kev loj ntawm daim duab (M):
M = -s'/s = h'/h
M = -(-30)/10 = 30/10 = 3
Daim duab raug nthuav dav 3 zaug.
Qhov siab ntawm qhov ntxoov ntxoo (h):
M = h' / h
3 = h' / 1 cm
h' = 3 (1 cm)
h' = 3 cm
Qhov siab ntawm tus duab ntxoov ntxoo yog 3 cm. Qhov siab ntawm tus duab ntxoov ntxoo zoo txhais tau tias tus duab ntxoov ntxoo ncaj.
C. Cov yam ntxwv ntawm cov duab ntxoov ntxoo
Raws li cov txiaj ntsig ntawm kev xam saum toj no, nws tuaj yeem xaus lus tias cov khoom ntawm cov duab ntxoov ntxoo yog:
Maya, ncaj thiab nthuav dav
6. Hauv lub teeb ci, ib lub teeb me me muab tso rau ntawm qhov chaw tsom ntawm daim iav concave. Qhov no yog kom lub teeb ci ntsa iab yog….
A. sib sau ua ke rau ib qho chaw
B. sib luag rau qhov chaw deb
C. kis mus rau txhua qhov chaw
D. tsim ib daim duab tiag tiag, txo qis
Kev Sib Tham
Yog tias lub teeb ci nyob ntawm qhov chaw tseem ceeb ntawm daim iav concave, lub teeb ci ntawm lub teeb ci ntaus rau ntawm qhov chaw ntawm daim iav concave thiab tom qab ntawd raug cuam tshuam los ntawm qhov chaw ntawm daim iav concave. Qhov kev taw qhia ntawm lub teeb ci ntsa iab yog sib luag rau lub axis tseem ceeb ntawm daim iav concave.
Cov lus teb yog B.
7. Muab ib yam khoom tso rau ntawm daim iav raws li pom hauv daim duab. Qhov loj ntawm daim duab uas tsim tau yog…..
A. 3 zaug
B. 2 zaug
C. 1 zaug
D. 1/2 zaug
Kev Sib Tham
Nws paub tias:
Qhov nrug ntawm yam khoom (s) = 60 cm
Qhov ntev ntawm lub teeb (f) = 20 cm
Saum toj no yog daim duab ntawm daim iav concave. Qhov chaw tseem ceeb ntawm daim iav concave yog qhov chaw uas lub teeb hla dhau, yog li qhov ntev ntawm daim iav concave yog qhov zoo.
Lo lus nug: Kev loj ntawm daim duab (M)
Lus teb:
Ua ntej, xam qhov nrug ntawm daim duab (s'), tom qab ntawd xam qhov loj ntawm daim duab (M) siv qhov nrug ntawm daim duab uas tau txais.
Qhov nrug ntawm duab ntxoov ntxoo:
1/f = 1/s + 1/s'
1/s' = 1/f – 1/s = 1/20 cm – 1/60 cm = 3/60 cm – 1/60 cm = 2/60 cm
s' = 60/2 cm = 30 cm
Kev loj ntawm daim duab (M):
M = s'/s = 30 cm / 60 cm = 1/2 zaug
Cov lus teb yog D.
8. Daim duab hauv qab no qhia txog kev tsim ib daim duab yog tias ib yam khoom raug muab tso rau 6 cm ntawm pem hauv ntej ntawm daim iav concave. Yog tias yam khoom raug txav ntawm nws qhov chaw qub 1 cm ntawm daim iav, ces qhov deb ntawm daim duab ntawm daim iav yog…..
A. 2,5 cm
B. 4,0 cm
C. 7,0 cm
D. 9,3 cm
Kev Sib Tham
Nws paub tias:
Qhov nrug ntawm yam khoom (s) = 6 cm
Qhov nrug ntawm duab ntxoov ntxoo (s') = 12 cm
Qhov nrug ntawm yam khoom thiab qhov nrug ntawm daim duab yog qhov zoo vim tias lawv yog qhov tseeb lossis raug lub teeb ci dhau los.
Lo lus nug: Yog tias qhov deb ntawm yam khoom (s) = 7 cm, ces qhov deb ntawm daim duab (s') yog…..
Lus teb:
Ua ntej, xam qhov ntev ntawm daim iav concave siv cov ntaub ntawv qhov deb ntawm cov khoom thiab qhov deb ntawm daim duab saum toj no.
1/f = 1/s + 1/s' = 1/6 + 1/12 = 2/12 + 1/12 = 3/12
f = 12/3 = 4 cm
Qhov ntev ntawm daim iav concave yog qhov zoo vim tias qhov chaw ntawm daim iav concave raug hla los ntawm lub teeb ci lossis yog qhov tseeb.
Yog tias qhov deb ntawm yam khoom yog 7 cm ces qhov deb ntawm daim duab yog:
1/s' = 1/f – 1/s = 1/4 – 1/7 = 7/28 – 4/28 = 3/28
s' = 28/3 = 9,3 cm
Cov lus teb yog D.
