When we press the bulb of a dropper with its nozzle kept in water, air in the dropper is seen to escape in the form of bubbles. Once we release the pressure on the bulb, water gets filled in the dropper. The rise of water in the dropper is due to
(a) pressure of water
(b) gravity of the earth
(c) shape of rubber bulb
(d) atmospheric pressure
(d) An atmospheric pressure
It is because, when we press the bulb of a dropper with its nozzle kept in water, air in the dropper is seen to escape in the form of bubbles. So, rise of the water in the dropper is due to the atmospheric pressure. When all the air escapes from the nozzle, then the atmospheric pressure, act on water, forces to fill the dropper.
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.
Image formed by a plane mirror is
(a) virtual, behind the mirror and enlarged
(b) virtual, behind the mirror and of the same size as the object
(c) real at the surface of the mirror and enlarged
(d) real, behind the mirror and of the same size as the object.
Describe the process of fertilization in human beings.
Explain why the sliding friction is less than the static friction.
Give reasons:
(a) Water is not used to control fires involving electrical equipment.
(b) LPG is a better domestic fuel than wood.
(c) Paper by itself catches fire easily whereas a piece of paper wrapped around an aluminium pipe does not.
What is a constellation? Name any two constellations.
In an experiment 4.5 kg of a fuel was completely burnt. The heat produced was measured to be 180,000 kJ. Calculate the calorific value of the fuel.
Choose the most appropriate answer:
(a) Internal fertilization occurs
(i) in the female body.
(ii) outside the female body.
(iii) in male body.
(iv) outside male body.
(b) A tadpole develops into an adult frog by the process of
(i) fertilization (ii) metamorphosis (iii) embedding (iv) budding
(c) The number of nuclei present in a zygote is
(i) none (ii) one (iii) two (iv) four
Name the petroleum product used for surfacing of roads.
A rocket has been fired upwards to launch a satellite in its orbit. Name the two forces acting on the rocket immediately after leaving the launching pad.
You are a member of the municipal body of your town.
Make a list of measures that would help your town to ensure the supply of clean water to all its residents.