Differentiate between retina and cornea.

Sheena entered a dimly lit room and could not see anything initially. However, after a while, she was able to see clearly. Can you explain the reason for this?

Suppose you are looking into a container filled with a liquid that is optically rarer than air. Will the apparent depth of the container be more or less?

Why is a glass slab not able to split white light like a prism?

Amita is studying in class $8$ of Government Model High School. Recently in her school, an NGO team helping visually- challenged people were invited. The NGO team came and took a session on the difficulty faced by visually-challenged people. They motivated the students to try a small experiment. The students were asked to go to sleep with a piece of cloth tied to their eyes. They had to stay blindfolded for a day so that they could experience the difficulties faced by visually-challenged people. In order to experiment this, Amita went to bed with a piece of cloth tied to her eyes. When she woke up the next morning, she was unable to see anything. Her mother came and helped her with the morning routines. Going to the bathroom, brushing her teeth, and having a bath were a real challenge. Amita felt completely useless and helpless because it took her more than one hour to complete these activities. Amita's friend Jenice came and helped her in getting ready for school. Walking to school with a stick in hand needed some learning. Amita was constantly afraid of falling and hurting herself. By the time it was evening, Amita was relieved that the day was over. Her experience helped her understand the difficulties of visually-challenged people. She thanked God for giving her the gift of sight. What is Braille?

Amita is studying in class $8$ of Government Model High School. Recently in her school, an NGO team helping visually- challenged people were invited. The NGO team came and took a session on the difficulty faced by visually-challenged people. They motivated the students to try a small experiment. The students were asked to go to sleep with a piece of cloth tied to their eyes. They had to stay blindfolded for a day so that they could experience the difficulties faced by visually-challenged people. In order to experiment this, Amita went to bed with a piece of cloth tied to her eyes. When she woke up the next morning, she was unable to see anything. Her mother came and helped her with the morning routines. Going to the bathroom, brushing her teeth, and having a bath was a real challenge. Amita felt completely useless and helpless because it took her more than one hour to complete these activities. Amita's friend Jenice came and helped her in getting ready for school. Walking to school with a stick in hand needed some learning. Amita was constantly afraid of falling and hurting herself. By the time it was evening, Amita was relieved that the day was over. Her experience helped her understand the difficulties of visually challenged people. She thanked God for giving her the gift of sight. How can we help visually challenged people?

Sudarshan always sleeps at night with the lights on, as he is scared of the dark. One night, Sudarshan was sleeping in his room when there was a power failure due to thunderstorm. Darkness, as well as disturbance due to thunders, woke him. On waking, Sudarshan could not see anything. He was terrified and removed the window curtains only to see no light outside, except a few infrequent streaks of lightning. He called his friend Rohan home and both of them sat and started talking. As they were talking, the power came back. Why was Sudarshan unable to see in the absence of a light source? What are unrealistic fears and how should we avoid them?