List conditions under which combustion can take place.
A chemical process in which a substance reacts with oxygen to give a product in the form of heat is called combustion. There are some conditions under which combustion takes place, which are as follows:
Describe with the help of a diagram an instrument which can be used to detect a charged body.
Sketch larynx and explain its function in your own words.
Arrange the following boxes in proper order to make a flow chart of sugarcane crop production.
Make a labelled diagram of a candle flame.
What is metamorphosis? Give examples.
The following Table shows the total power shortage in India from 1991– 1997. Show the data in the form of a graph. Plot shortage percentage for the years on the Y-axis and the year on the X-axis.
Make sketches of animal and plant cells. State three differences between them.
What is a constellation? Name any two constellations.
Describe the construction of a kaleidoscope.
Complete the crossword with the help of clues given below:
Across
1. This is necessary for photosynthesis.
3. Term for component present in the cytoplasm.
6. The living substance in the cell.
8. Units of inheritance present on the chromosomes.
Down
1. Green plastids.
2. Formed by collection of tissues.
4. It separates the contents of the cell from the surrounding medium.
5. Empty structure in the cytoplasm.
7. A group of cells.
Differentiate between regular and diffused reflection. Does diffused reflection mean the failure of the laws of reflection?
Suggest three measures to protect ourselves from lightning.
List changes in the body that take place at puberty.
Which zone of a flame does a goldsmith use for melting gold and silver and why?
The bulb does not glow in the setup shown in Fig.14.10. List the possible reasons. Explain your answer.
Describe the threat to the beauty of the Taj Mahal.
Identify the part which vibrates to produce sound in the following instruments:
(a) Dholak (b) Sitar (c) Flute
Give examples which indicate that nylon fibres are very strong.
Make a labelled diagram of a candle flame.
Fill in the blanks :
(a) Fossil fuels are , and .
(b) Process of separation of different constituents from petroleum is called .
(c) Least polluting fuel for vehicle is .