Question

Cả 2 bài ạ

Answer 1

2.10.

a)\(R=\dfrac{U}{I}=\dfrac{6}{0,15}=40\Omega\)

b)Nếu tăng U thì R có thay đổi.

\(\dfrac{U_1}{U_2}=\dfrac{R_1}{R_2}\Rightarrow\dfrac{6}{8}=\dfrac{40}{R_2}\Rightarrow R_2=\dfrac{160}{3}\Omega\)

\(I_2=\dfrac{U_2}{R_2}=\dfrac{8}{\dfrac{160}{3}}=0,15A\)

Answer 2

2.11.

a)\(I_1=\dfrac{U}{R}=\dfrac{3,2}{20}=0,16A\)

b)U không đổi.\(\Rightarrow\dfrac{I_1}{I_2}=\dfrac{R_2}{R_1}\)

Mà \(\dfrac{I_1}{I_2}=\dfrac{1}{0,8}=\dfrac{5}{4}\)\(\Rightarrow\dfrac{R_2}{R_1}=\dfrac{5}{4}\Rightarrow R_2=25\Omega\)

Answer 3

2.10

\(a,R=\dfrac{U}{I}=\dfrac{6}{0,15}=40\Omega\)

\(b,\)

nếu tăng \(U\) thì \(R\) có thay đổi

\(\dfrac{U_1}{U_2}=\dfrac{R_1}{R_2}\Rightarrow\dfrac{6}{8}=\dfrac{40}{R_2}\Rightarrow R_2=\dfrac{160}{3}\Omega\) 

\(I_2=\dfrac{U_2}{R_2}=\dfrac{\dfrac{8}{160}}{3}=0,15A\)

2.11

\(a,I_1=\dfrac{U}{R}=\dfrac{3,2}{20}=0,16A\)

\(b,\)

\(U\) không đổi . \(\Rightarrow\dfrac{I_1}{I_2}=\dfrac{R_2}{R_1}\)

Mà:\(\dfrac{I_1}{I_2}=\dfrac{1}{0,8}=\dfrac{5}{4}\Rightarrow\dfrac{R_2}{R_1}=\dfrac{5}{4}\Rightarrow R_2=25\Omega\)