10 th Sci.I, Lenses...2, 10 वी, विज्ञान I, भिंगे व त्यांचे उपयोग, 🎷
दररोज थोडी थोडी वैज्ञानिक माहिती मिळवण्यासाठी आपल्या व्हाट्सॲप ग्रुप ला जॉईन होऊ शकता. Join होण्यासाठी खाली दिलेल्या लिंक वर क्लिक करून आपल्या ग्रुप मध्ये सामील व्हावे. जॉईन होण्यासाठी निळ्या लिंक ला स्पर्श करावा.
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-👉 🔴 माहिती विज्ञानाचा 🎷 🔴
ग्रुप वर जॉईन का व्हावे? याचे कारण....
• आपण आयुष्यभर विद्यार्थीच असतोत ,मग चला तर दररोज थोडे थोडे विज्ञान शिकू.
• दररोजच्या जीवनात खूप विज्ञान आहे, या प्रयत्नातून काही विज्ञान आपणास समजले. ज्ञानात भर पडली तर आनंद वाढतो.
• एखाद्याने प्रश्न विचारला व आपल्याला त्या प्रश्नाचे जर उत्तर देता आले तर तो आनंद वेगळाच असतो.
• तुम्ही विद्यार्थी आहात तर शिकले पाहिजे, वयाने मोठे भाऊ-बहीण आहात तर लहान मुलांना अभ्यासात मदत करता आली पाहिजे, पालक आहात तर मुलांचा अभ्यास घेता आला पाहिजे, आजोबा/ आजी आहात तर नातवाच्या प्रश्नांचे उत्तर देता आले पाहिजे.
• विज्ञानातील बराचसा भाग हा शाश्वत आहे, त्यामुळे बरेच विज्ञान आपल्याला आले पाहिजे.
• देशाची प्रगती करायची असेल तर शास्त्रज्ञ तयार झाले पाहिजेत. शास्त्रज्ञ तयार होण्यासाठी विज्ञान समजले पाहिजे.
• आणखीन कितीतरी कारणे आपणास सांगता येतील, यासाठी सस्नेह निमंत्रण🙏🎷
आज बऱ्याच जणांचे सामाजिक आरोग्य बिघडत आहे. जेवढे तंत्रज्ञान प्रगत होत आहे त्याच प्रमाणात जीवनशैलीत बदल होत चालले आहेत. बऱ्याच व्यक्ती अधिकाधिक आत्मकेंद्री होत आहेत.
"कासवाच्या गतीने का होईना पण रोज थोडी थोडी प्रगती करा, खूप ससे येतील आडवे, बस त्यांना हरवायची हिंमत कायम ठेवा.🎷🥁🎸🎺
We studied six different images obtained through a convex lens / magnifying glass. It is becoming easier to remember if we can draw these six images in a single diagram.
Some tricks for remembering six images.
1. As the object moves towards the lens, the image moves away from the optical center (O) (for the first five figures).
2. As the object moves towards the lens, the size of the image gradually increases.
🎺 Images formed by concave lenses
1. Position of the object: at infinity
Position of the image: on the first focus F1
Size of the image:- pointed
Nature of the image:- virtual and erect.
B. Position of the object:- anywhere between optical center O and infinity
Position of the image:- between optical center O and focus F1
size of the image:- small
nature of the image:- virtual and Erect.
🥁 Cartesian sign convention for the lens.
1. The object should always be placed to left the lens.
2. All distances should be measured from the optical center ( O ).
3. A. Those distances measured above the principle axis should measure positive +ve.
B. Those distances that are measured below the principle axis should be measured as negative -ve.
4. A. The distance measured in the propagation of light rays from the optical center is measured as a positive +ve .
B. The distance measured to the left of the optical center is taken to be negative -ve.
5 A. The focal length (f) of a convex lens is positive +ve.
B. The focal length (f) of a concave lens is negative -ve.
Lens formula
v - the distance of the image from the optical center
u - the distance of the object from the optical center
f - the focal length of the lens.
It is necessary to use the sign convention properly when we use the lens formula.
Magnification (m)
The ratio of the height of the image h2 to the height of the object h1 is called magnification due to a lens.
Power of a lens
The power (P) of a lens is defined as the capacity of a lens to converge or diverge incident rays.
The unit of the power of a lens - Dioptre (D)
🎷 Human eye
1. Cornea:- A very thin transparent membrane on the human eye is called a cornea.
Function maximum light is refracted towards the lens.
2. Iris:- a dark fleshy screen behind the cornea is called the iris. The color of the iris is different for different people such as Black, brown, blue, grey, white, etc.
Function controls the light ray.
3. Pupil:-At the center of the iris, there is a small hole called The pupil.
Function:- The pupil controls the amount of light entering the eye. If the light is dim pupil widens and if the light is too bright, the pupil contracts.
4. Lens: Behind the pupil, a double convex transparent crystalline lens is present.
Function: The lens creates real and inverted images of an object on the retina/screen inside the eye.
5. Retina:- light-sensitive cells are present on the screen of an eye It is called the retina.
Function:- Retina cells get excited when light falls on them and generate electric signals.
Function of Optic nerve:- electric signals are conveyed to the Brain through the optic nerve.
🎺 Power of accommodation
Ans. A. Definition:- The capacity of the lens to change its focal length as per need is called its power of accommodation.
B. When we see nearby objects, the lens becomes rounded and its focal length decreases so we can see nearby objects clearly.
C. When we see distinct objects the lens of the eye becomes flat and its focal length increases, due to which we can see distinct objects clearly.
🎸 Minimum distance of distinct vision
The minimum distance of an object from a normal eye can see clearly without any stress on the eye is called a minimum distance of distinct vision. For a normal eye, the near point is 25 cm.
🥁 Some funny stuff
* The diameter of the eyeball is approximately 2.4 cm.
* The focal length of a healthy human eye is 2 cm.
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