Trong thí nghiệm I-âng (Young) về giao thoa ánh sáng, tại điểm M trên màn có vân sáng bậc 5. Di chuyển màn ra xa thêm 20 cm, tại điểm M có vân tối thứ 5. Khoảng cách từ màn quan sát đến hai khe trước khi dịch chuyển là:  

Chia sẻ

Một số câu hỏi khác có thể bạn quan tâm.

• Choose the best answer for the following sentence:

  A beauty contest is a competition based largely ______________  the beauty of the

  contestants’ physical appearance.

   

• Choose the best answer for the following sentence:

  You have not participated __________ any of our competitions before, have you?

   

• Choose the best answer for the following sentence:

  _________ a contest requires a good preparation.

   

• Choose the best answer for the following sentence:

  She looked at me with admiration, ____________.

   

• Choose the best answer for the following sentence:

  _________ a winner in an eloquence, you must be very competent in public speaking.

   

• Choose the best answer for the following sentence:

  ______________ The semi-finals, he went on to play in the finals.

   

• Choose one sentence that has the same meaning as the root one:

  She is wearing a nice dress. Her husband presented it to her on their 10th wedding anniversary.

• Choose one sentence that has the same meaning as the root one:

  We ordered wine, not beer.

• Choose a word that has different stress pattern:

  competitive              entertainment                   disqualify           especially                                                    

   

• Choose one sentence that has the same meaning as the root one:

  You can send the report by fax or you can send it by email.