লেন্স ও দর্পণ
Four convex lenses A B, C and D have focal lengths of 5 cm, 5 m, 50 cm and 15 cm respectively.Which one would you choose as a magnifying glass?
Answer is A.
When the object is located at a location in front of the focal point, the image will always be located somewhere on the same side of the lens as the object. Regardless of exactly where in front of F the object is located, the image will always be located on the object's side of the lens and somewhere further from the lens. The image is located behind the object.
Therefore, a converging lens produced a virtual image when the object is placed in front of the focal point. For such a position, the image is magnified and upright, thus allowing for easier viewing. Hence, the focal length of the lens should be as small as possible.
Hence, the lens A with a focal length of 5 cm will be chosen as a magnifying glass.
Ai এর মাধ্যমে
১০ লক্ষ+ প্রশ্ন ডাটাবেজ
প্র্যাকটিস এর মাধ্যমে নিজেকে তৈরি করে ফেলো
উত্তর দিবে তোমার বই থেকে ও তোমার মত করে।
সারা দেশের শিক্ষার্থীদের মধ্যে নিজের অবস্থান যাচাই
একটি লেন্সের ক্ষমতা 1 dioptre হলে এর ফোকাস দৈর্ঘ্য কত?
A concave mirror has a focal length of 25 cm. At which of the following distance should a person hold his face from this concave mirror so that it may act as a shaving mirror ?
Fill in the blanks:
The rays which are parallel to the principal axis of a concave mirror on reflection, meet at ____
A magnifying glass is what kind of lens, and where do where should I place the lens relative to the object to see an image larger than the object and right-side-up? (f stands for the focal length of the lens.)
