Cov Lus Nug Piv Txwv Txog Lub Suab

4 Piv Txwv ntawm Cov Lus Nug Txog Lub Suab

1. Cov ntsiab lus A thiab B nyob ntawm qhov deb ntawm 4 m thiab 9 m ntawm qhov chaw suab. Yog tias kuv_A thiab kuv_B txhua tus ntawm lawv yog lub suab nrov ntawm qhov chaw A thiab qhov chaw B, ces kuv_A : Kuv_B yog ...

A. 3: 2

B. 4: 9

C. 9: 4

D. 16: 81

E. 81: 16

Kev Sib Tham

Nws paub tias:

Qhov deb ntawm qhov chaw A ntawm qhov chaw suab (r)_A) = 4 'meter'

Qhov deb ntawm qhov chaw B ntawm qhov chaw suab (r)_B) = 9 'meter'

Lub suab nrov ntawm qhov chaw A = I_A

Lub suab nrov ntawm qhov chaw B = I_B

Nug: I_A : Kuv_B

Lus teb:

Cov mis rau kev sib raug zoo ntawm qhov muaj zog thiab qhov deb:

Cov lus teb yog yog E.

2. Lub suab nrov ntawm lub tshuab xaws thaum nws ua haujlwm yog 10^-9 Wm^-2Rau qhov muaj zog ntawm lub suab ntawm 10^-12 Wm^-2, ces lub suab nrov ntawm 10 lub tshuab xaws zoo sib xws uas ua haujlwm yog…..
A. 400 dB

B. 300 dB

C. 40 dB

D. 30 dB

E. 20 dB

Kev Sib Tham

Nws paub tias:

Kuv = 10^-9 W / m²

I_o = 10^-12 W / m²

x = 10 os

Nug: TI 10 tshuab xaws?

Lus teb:

TI 10 lub tshuab = TI 1 lub tshuab + 10 cav x

TI = 30 + 10 log 10

TI = 30 + 10 log 10¹

TI = 30 + (1)(10)(log 10)

TI = 30 + 10

TI = 40 dB

Cov lus teb yog C.

3. Lub suab nrov ntawm ib tug muv uas nrov nrov yog 10 dB. Yog tias lub suab nrov ntawm txhua tus muv raug suav tias zoo ib yam thiab tib neeg lub pob ntseg hnov ​​tau yog 10 dB.^-12 Wm^-2 Yog li ntawd, lub zog ntawm lub suab nrov ntawm 1000 tus muv yog ...

A. 10^-8 Wm^-2

B. 10^-7 Wm^-2

C. 10^-6 Wm^-2

D. 10^-5 Wm^-2

E. 10^-4 Wm^-2

Kev Sib Tham

Nws paub tias:

TI = 10 dB

I_o = 10^-12 W / m²

x = 1000 os

Nug: TI 1000 muv?

Lus teb:

4. Lub suab ntawm lub tsheb kauj vab thaum lub suab nrov ua rau muaj zog ntawm 40 dB, thaum lub suab ntawm lub tsheb kauj vab thaum lub suab nrov ua rau muaj zog ntawm 60 dB (I_o = 10^-12 W m^-2 ). Yog tias 100 lub suab raj maus taus thiab 10 lub suab raj tsheb raug tshuab tib lub sijhawm, ces qhov sib piv ntawm qib zog ntawm maus taus rau lub tsheb yog ....

A. 5: 6

B. 6: 7

C. 7: 8

D. 8: 9

E. 9: 10

Kev Sib Tham

Nws paub tias:

Qib zog (TI) ntawm lub suab tsheb kauj vab = 40 dB

Lub zog ntawm lub tsheb lub suab nrov (TI) = 60 dB

Qhov tsawg kawg nkaus uas tib neeg hnov ​​tau (Kuv_o) qhov nruab nrab = 10^-12 W m^-2

Lo lus nug: TI piv ntawm 100 lub maus taus rau TI ntawm 10 lub tsheb yog dab tsi?

Lus teb:

Qhov kev sib piv ntawm TI 100 maus taus nrog TI 10 lub tsheb yog:

60: 70

6: 7

Cov lus teb yog B.

Qhov chaw nug lus:

Cov Lus Nug Txog Kev Xeem Physics Hauv Tebchaws Rau Tsev Kawm Ntawv Theem Siab/Tsev Kawm Ntawv Theem Siab Ua Haujlwm