Which is not a part of the human eye?
Important Questions on Light
Read the following passage and answer the following questions.
Lenses in our eyes
In class 6 you learnt about pinhole camera. The human eye also works as a pinhole camera with two lenses. The pupil acts as a pinhole. Light falls on the cornea which acts as a converging lens. Then it falls on 'the lens’ which is behind the cornea. Through the lens, the light falls on the retina to form a real image. To focus on objects, animals can move the lens or change its shape. Fish move their lens backward and forward to focus the image of objects on their retina. Mammals change the shape of their lens. When we have to focus on the objects at a distance our lenses become thin. Due to this the light coming from the object bends less. When we focus on nearby objects, the lenses become thicker. As a result the light coming from the object bends more and falls on the retina. The shape of lenses is changed by muscles around it. When the lens needs to be thin, the muscles relax and when the lens needs to be thick, they contract. For this reason, when you read for a long time, your muscles are contracted continuously and your eyes feel tired.
How do the fish focus on objects?
Look into your friend’s eye. Observe the size of the pupil. Throw light on her eye with a torch. Observe the pupil now. Switch off the torch, and observe her pupil once again. Do you notice any change in the size of the pupil? In which case was the pupil larger? Why do you think it was so? In which case do you need to allow more light in the eye, when the light is dim or bright?
Gurmit wanted to perform the above activity using a laser torch. Her teacher advised her not to do so. Can you explain the basis of the teacher's advise?
Statement : The optic nerve receives messages from the sclera.
Select the correct option.
Read the following passage and answer the following questions.
Lenses in our eyes
In class 6 you learnt about pinhole camera. The human eye also works as a pinhole camera with two lenses. The pupil acts as a pinhole. Light falls on the cornea which acts as a converging lens. Then it falls on 'the lens’ which is behind the cornea. Through the lens, the light falls on the retina to form a real image. To focus on objects, animals can move the lens or change its shape. Fish move their lens backward and forward to focus the image of objects on their retina. Mammals change the shape of their lens. When we have to focus on the objects at a distance our lenses become thin. Due to this the light coming from the object bends less. When we focus on nearby objects, the lenses become thicker. As a result the light coming from the object bends more and falls on the retina. The shape of lenses is changed by muscles around it. When the lens needs to be thin, the muscles relax and when the lens needs to be thick, they contract. For this reason, when you read for a long time, your muscles are contracted continuously and your eyes feel tired.
How does the lens change shape when we focus on distant objects?
Read the following passage and answer the following questions.
Lenses in our eyes
In class 6 you learnt about pinhole camera. The human eye also works as a pinhole camera with two lenses. The pupil acts as a pinhole. Light falls on the cornea which acts as a converging lens. Then it falls on 'the lens’ which is behind the cornea. Through the lens, the light falls on the retina to form a real image. To focus on objects, animals can move the lens or change its shape. Fish move their lens backward and forward to focus the image of objects on their retina. Mammals change the shape of their lens. When we have to focus on the objects at a distance our lenses become thin. Due to this the light coming from the object bends less. When we focus on nearby objects, the lenses become thicker. As a result the light coming from the object bends more and falls on the retina. The shape of lenses is changed by muscles around it. When the lens needs to be thin, the muscles relax and when the lens needs to be thick, they contract. For this reason, when you read for a long time, your muscles are contracted continuously and your eyes feel tired.
How many lenses are there in our eyes?
