Why is the colour of a leaf kept in the dark frequently yellow, or pale green? Which pigment do you think is more stable?

The mean value can be calculated from both ungrouped and grouped data. Which one do you think is more accurate? Why?

Which colour has more speed in glass prism? Blue or yellow ?

Which colour from violet and Red is more refracted ? Why

To demonstrate the process of thermoelectric production with a model. Apparatus and materials: Pressure cooker, pipe, tennis ball, metal sheet, dynamo, bulb. Procedure : rarr Take a table-tennis ball and make three slits into it. rarr Put semicircular fins cut out of a metal sheet into these slits. rarr Pivot the tennis ball on an axle through its centre with a straight metal wire fixed to a rigid support. Ensure that the tennis ball rotates freely about the axle. rarr Now connect a cycle dynamo to this. rarr Connect a bulb in series. rarr Direct a jet of water or steam produced in a pressure cooker at the fins. Note down your observation. Observation : The bulb gets lighted. Which energy conversion do you think is taking place in this model ?

Municipal corporation insists people to dispose wet wastes in green coloured dustbin and dry wastes in blue coloured dustbin for their domestic waste disposal. Municipal waste collection van collects domestic wastes only if wet and dry wastes are separated. What is use of dry wastes? Which concept do you think from five R's ?

One day in the morning, Ramesh filled up 1/3 bucket of hot water from geyser, to take bath. Remaining 2/3 was to be filled by cold water (at room temperature) to bring mixture to a comfortable temperature. Suddenly Ramesh had to attend to something which would take take some times, say 5-10 minutes before he could take bath. Now he had two options : (1) fill the remaining bucket completely by cold water and then attend to the cork, (2) first attend to the work and fill the remaining bucket just before taking bath. Which option do you think would have kept water warmer ? Explain.

We saw in this chapter that there are four main stakeholders when it comes to forests and wildlife. Which among these should have the authority to decide the management of forest produce? Why do you think so?

You are given four sources of light each on providing a light of a single colour - red, blue green and yellow. Suppose the angle o refraction for a beam of yellow ligh corresponding to a particular angle o incidence at the interface of two media is 90° Which of the following statements is correct i the source of yellow light is replaced with tha of other lights without changing the angle o incidence ?