Một ống dây dài với 2000 vòng trên một đơn vị chiều dài đặt trong không khí . Cường độ dòng điện chạy trong ống dây \[ I=5\left( A \right) \] . Tính độ lớn cảm ứng từ bên trong ống dây.
A.\[ 7\pi {{.10}^{-3}}\left( T \right) \].
B.\[ 5\pi {{.10}^{-3}}\left( T \right) \].
C.\[ 4\pi {{.10}^{-3}}\left( T \right) \].
D.\[ 6\pi {{.10}^{-3}}\left( T \right) \].

Tại tâm của dòng điện tròn có bán kính 5cm người ta đo được cảm ứng từ \[ B=5,{{2.10}^{-5}}T \] . Cường độ dòng điện chạy qua vòng tròn có giá trị gần nhất với giá trị nào sau đây?
A.3 A.
B.5 A.
C.6 A.
D.4 A.

Pick out the word whose underlined part is pronounced differently from that of the other words
A.changed
B.collected
C.formed
D.viewed

Mark the letter A, B, C, or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions
A.harvest
B.part
C.particular
D.superstar

Mark the letter A, B, C, or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions.
A.flute
B.mute
C.absolute
D.pollute

Pick out the word whose underlined part is pronounced differently from that of the other words
A.attended
B.celebrated
C.displayed
D.invited

Mark the letter A, B, C or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following question
A.unbelievable
B.volume
C.reunite
D.uniform

Mark the letter A, B, C or D to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions.
A.clothes
B. goose
C. horse
D. crisis

In these groups, three of the words begin with the same consonant sound and one of the words begins with a different sound. Choose the one with the different sound.
A.happy
B.how
C.honest
D.healthy

Mark the letter A, B, C, or D on youranswer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions
A.developed
B.eradicated
C.needed
D.contributed