Answer the following :
How did we obtain all the information about the universe ? If we look at the sky at night we see only planets and stars , then how did we get information about the other components of the universe ?

Answer the following : How can we measure water flow emerging from a pipe ?

Answer the following questions: Give detailed information about how the merchants of olden times used a magnet while travelling.

Answer the following : How will you explain the statement 'we cannot see the objects in a dark room ' ?

Answer the following questions. How can we get the required amount of energy by connecting solar panels?

State whether the following statements are true or false : ( If a statement is false , correct it and rewrite it.) : Due to the light sensitive cells in the eye , we get information about the brightness or dimness of the object and the colour of the object.

Select the appropriate option and complete the following paragraph. (cornea, faint, conical, rod, image, coloured, retina, colours, myopic, presbyopic, colour blind) The ____ in our eyes consists of many light sensitive cells. These cells are shaped like a rod and like a cone. The ____ shaped cells give information about the intensity of light to the brain. The ____ cells give information about the colour of the object to the brain. Brain processes all the information received and we see the actual image of the object. Rod shaped cells respond to ___ light also but conical cells do not. Thus we perceive ____ only in bright light. Some people cannot recognize few colours or cannot distinguish between different colours. These persons are said to be _____. Apart from not being able to distinguish between different colours, their eye sight is normal.

Answer the following questions : During winter , sometimes we see a white trail at the back of a flying aeroplane in a clear sky. Explain why.

Answer the following questions : Observe the following figure and answer the questions How can we get different magnifications in this optical instrument ?

Answer the following questions : Observe the following figure and answer the questions : How can we get different magnifications in this optical instrument ?