Giai
cu
nen W = Wd + Wt O Wt = W - Wa
cu'
2
LI'
LI'
8
2
8
2
Vay chgn dap an D.
Cdu 17: Trong quang pho cua nguyen tuf hidro, neu biet h\idc song dai
nhat cua vach quang pho trong day Laiman la X, i va h\i6c song cua
vach ke vdfi no trong day nay la ^2 thi h\idc song
pho
cua vach quang
trong day Banme l a :
A. (X,-^,)-
c.
B.
+
D.
Giai
Difa vac scf do chuyen mufc nSng
Iifpng, ta c6:
hfi = E i - E o
(1)
hf2 = E2 - Ee
(2)
hf„ = E2 - E l
(3)
E3-
E2-
K
Ei-
TrCf ve vdi ve (2) va (1) ta difpc:
Eo-
hf„ = hf2 - hfi
1-v he ^ he he
V i hf = — nen — =
he
.
=>^„ =
Vay chgn dap an B.
Cdu 18: Phat bieu nao sau day l a s a i k h i noi ve dao dong cua con iSc
dcfn (bo qua liic can cua moi triTdng)?
A. Vdri dao dong nho thi dao dong cua con lac l a dao dong dieu h6a.
B. K h i vat nang d vi tri bien, cd nang cua con lac bang the nang
cua n6.
C. Chuyen dong cua con iSc tCf vi tri bien ve vi tri can bang la
nhanh dan.
D. K h i vat nang di qua vi tri can bang, thi trong
ILTC
tac dung len
no can Vlng vdi life cSng cua day.
Giai Chi l e t d6 thi TS DH, CD Mdn V$t If
9