Предмет: Физика, автор: NeedForRead9

определите длину никелевой проволоки если при напряжении на ее концах в 45 В сила тока равна 2,25А. площадь поперечного сечения проволоки 1мм квадратный.

Ответы

Автор ответа: ZhanVero
0

U=45Oм

i=2/25A

S=1mm(2)

p(ро)=0,4Oм*mm(2)/м

l-?

R=pl/S

l=RS/p

R=U/i

U/i=pl/S

US=Ipi

l=US/pi

l=(45*1)/(0.4*2.25)=45/0,9=50м

Ответ:50м

 

Интересные вопросы
Предмет: Английский язык, автор: tursunbaibaidosov196
do homework every day?



a) Do you have

b) You have to

c) Do you have to

d) Have you got



2. How many people . . . in your class?

a) is there

b) are there

c) be there

d) there are



3. My brother . . . work very hard.

a) have to

b) has

c) has got

d) has to



4. Cars and factories . . . the air.

a) save

b) waste

c) protect

d) pollute



5. What are you going to . . . tonight?

a) doing

b) do

c) did

d) does



6. Have you ever been to . . . ?

a) an Africa

b) a Africa

c) Africa

d) the Africa



7. You drive too . . . .

a) fast

b) faster

c) the fastest

d) very fast



8. My sister lives in . . . house.

a) old

b) a old

c) an old

d) he old



9. You’re . . . at English than I am.

a) the best

b) better

c) best

d) good



10. I . . . write my name when I was four.

a) did

b) can

c) was

d) could



11. If you want to use e-mail, click . . . this icon.

a) to

b) up

c) out

d) on



12. “Has she ever failed an exam?”

“No, she . . . .”

a) didn’t

b) haven’t

c) hasn’t

d) hasn’t failed



13. . . . the first man on the moon?

a) Who was

b) Who did

c) Who were

d) What was



14. She . . . her dinner at the moment.

a) eat

b) eating

c) eats

d) is eating



15. We mustn’t . . . . My mum is waiting.

a) being late

b) to be late

c) late

d) be late



16. She always eats dinner . . . two o’clock.

a) at

b) to

c) in

d) on



17. You should . . . at night. It’s dangerous in the dark.

a) to be careful

b) be careful

c) being careful

d) careful





18. Where were you . . . night?

a) yesterday

b) ago

c) before

d) last



19. Where _____ from?

a) Hans come

b) does Hans come

c) does Hans coming

d) Hans came



20. What _____ tonight?

a) do you do

b) you do

c) are you doing

d) did you do

Помогите пожалуйста ​