Soil — Science STD 7 — Question

State the characteristics of the image formed by a plane mirror.

Explain the various types of sewage.

Jaya returned from school and found that her grandmother was scolding their maid Rani, as she did not come the day before. The maid told that her son was passing watery stools frequently that's why she did not come. Jaya's mother who was listening the discussion came to them and told Rani not to come for coming 3-4 days. She also suggested to give her son a solution of sugar and salt in (boiled and cooled) water, many times a day for fast recovery. Jaya was surprised. She rushed to her mother and asked the scientific reason for it. Her mother smiled and explained her the importance of this solution.
(i) Name the term used to describe the condition in which a person passes out watery stools.
(ii) Name the solution of sugar and salt in water. Why is it given to a person suffering from this condition?

Assume, a person is standing in front of a plane mirror. The distance between the mirror and his image is 6m. If the person moves 2 m towards the plane mirror, what would be the distance between the person and his image?

One day, Ramesh's friends were performing their respective experiments given by their teacher. While sitting in the practical lab instead of performing experiment, Ramesh was playing with his meter scale. All of the sudden, he held the scale in his hand and started moving in front of tubelight, then he observed the seven colours of white light. After sometimes, he got scolded by his lab teacher for not performing the experiment.
(i) Give the name of phenomenon that leads to the formation of band of seven colours.
(ii) Name the constituent colours of white light.
(iii) Mention the values shown by Ramesh here.

Draw a labelled diagram to show (a) open circuit (b) closed circuit and explain.

Last Sunday Girish's mother, Priyanka was preparing the dinner in her kitchen for Girish and his father. Both of them were feeling so much hungry and they sat ideally on their respective chairs and having empty plates and spoons on their dinning table. They were shouting like a 5 years old child that they wanted the dinner so eagerly to fulfil their stomach. After sometime, Girish's mother served the cooked food to both of them and when Girish was just about to eat the rice with the help of spoon, he noticed that the spoon has such a shining surface that it reflected the light rays incident on it.
(i) Explain the importance of shining surface in the reflection of light.
(ii) Name the type of spherical mirror represented by the shining steel spoon.
(iii) Mention the values shown by Priyanka here towards her family

Visit a forest with your parents by taking permission from the respective authority (forest officials).
(i) Make a list of the things you see in the forest.
(ii) Try to recognise various types of trees and different layers formed by them.