Vật sáng AB đặt vuông góc với trục chính của một TKHT (điểm A nằm trên trục chính), và cách TKHT 18 cm. TKHT có tiêu cự 12cm. a/. Vẽ hình, nhận xét ảnh A’B’ và xác định vị trí của ảnh A’B’ so với TKHT. b/. Muốn ảnh A’B là ảnh thật cao bằng vật thì phải di chuyển vật AB lại gần hay ra xa TKHT? Di chuyển AB một đoạn bao nhiêu cm?

Các câu hỏi liên quan

Part I: Using the Colon Directions: Given below are sentences that require colons. Use the colon to correctly complete each sentence. Example: My mom said to her son “get home from school on time.” Answer: My mom said to her son: “get home from school on time.” 1. The man said it best “We are not afraid!” ______________________________________________________________________ 2. My dad hinted where the Easter egg was under the bushes. ______________________________________________________________________ 3. There was one thing left to do arrive with excitement. ______________________________________________________________________ 4. John spoke at the ceremony gallantly “We are all happy to be here.” ______________________________________________________________________ Part II: Listing with Colon Directions: Given below are sentences that require colons. Use the colon to correctly complete each sentence. 1. The bookstore specializes in three subjects art, architecture, and graphic design. ______________________________________________________________________ 2. David has the ingredients sugar, water, milk, and potatoes. ______________________________________________________________________ 3. I woke up at seven thirty a.m. in the morning. ______________________________________________________________________ 4. The school play includes five dances rumba, salsa, and samba. ______________________________________________________________________ Part III: Colons Introduce Quotation Directions: Re-Write each given sentence. Add a colon where necessary that indicates a quotation. Some sentences do not need a colon. Example: My mom said to her son: “get home from school on time.” 1. My dad told my brother “get your homework done.” ______________________________________________________________________ 2. Larry said to Sam “thanks for coming to dinner.” ______________________________________________________________________ 3. The woman spoke to the crowd “Everyone is equal” ______________________________________________________________________ 4. “What way are you going?” asked my friend. ______________________________________________________________________ Part IV: Writing Sentences with Colons Directions: Re-Write each given sentence. Add a colon where necessary that begins the explanation. 1. I went to the mall it was busy and filled with people. ______________________________________________________________________ ______________________________________________________________________ 2. The teacher gave out the directions no talking and listen quietly. ____________________________________________________________________________________________________________________________________________ 3. I brought my sports equipment to the gym a basketball shorts and water. ____________________________________________________________________________________________________________________________________________ 4. The food arrived at the table it was delicious and smelled good. ____________________________________________________________________________________________________________________________________________