Explain the process of nutrition in amoeba with the help of a neat labelled diagram
Write three points of difference between breathing and respiration
Write any three disadvantages associated with hydro power plant.
Villagers in Mohan’s village use their animal dung as dung cakes for fuel requirement. When
Mohan returned to his village, after completing his studies from nearby city, he suggested in
village panchayat to set up a biogas plant in the village.
(i) Do you think Mohan’s suggestion is appropriate ? Give reason for your answer.
(ii) Which quality of Mohan gives inspiration to villagers
How will the resistance of a wire change when :
(i) its length is doubled.
(ii) its diameter is doubled.
(iii) its temperature is increased.
For an electric heater rated 4 kW; 200 V. Calculate :
(i) the current required
(ii) the resistance of the heater
(iii) the energy consumed in 1 hour
Write any three characteristics of a good fuel
Sheelu was visiting her city after one year. Since during summers there were frequent power
breakdown, she was a bit uncomfortable thinking about the unruly traffic in the city without
traffic signals. But to her surprise, she found that all the traffic signals were working, inspite
of the load shedding. She saw that all the traffic signals were powered by the solar cell
panels. At one particular signals she saw that some naughty boys were trying to break the
solar panel. She stopped them from doing so and explained them not to do so.
(a) State the value exhibited by Sheelu.
(b) Explain any two arguments in favour of using solar panels for running traffic signals
for managing traffic.
How are magnetic field lines of a bar magnet drawn. “Two field lines are never found to
intersect each other”. Give reason to justify this statement.
Explain, how is electricity generated from wind energy on a commercial scale?
What is meant by solenoid? How does a current carrying solenoid behave? Give its main use.
Plants absorb water from the soil. Explain how does the water reach the tree top ?
Trace the sequences of events through a reflex arc which occur when a bright light is focussed
on your eyes.
Name the hormone which is released into the blood when its sugar level rises. Name
the organ which produces this hormone and its effect on blood sugar level. Also
mention the digestive enzymes secreted by this organ with one function of each
Explain the need of Chemical communication in multicellular organisms
A metal ‘P’ when exposed to the moist air for longer period of time, loses its shiny brown
surface and gains a green coat. Why has this happened ? Identify the metal. Write the name
and chemical formula of this green colored compound. List two ways to prevent this process.
You must have tasted or smelt the fat containing food material left for a long time. Such foods taste
and smell bad. What is the reason for this ? Name the phenomenon responsible for it. List two
measures for its prevention.
Draw a nerve cell and label on it the following :
Nucleus, Dendrite, Axon
Write the chemical formula of washing soda. How can it be obtained from baking soda ? Name two
industrial uses of washing soda.
Can oxidation and reduction take place alone? Why or why not ? What are such reactions
called ?
List three main parts of hind brain and explain their functions briefly.
State three reasons for the following facts :
(i) Sulphur is a non-metal.
(ii) Magnesium is a metal.
One of the reasons must be supported with a chemical equation.
You are provided with three test tubes A, B and C which contain distilled water, acidic
solution and basic solution respectively. If you are given blue litmus paper only, how will
you identify the contents of each test tube
When hydrogen gas burns in presence of oxygen, water is formed and when
electrolytic reduction of water is done then hydrogen and oxygen gases are formed.
State the types of chemical
reactions :
(i) in the first case
(ii) in the second case
Name the following :
(i) A gland present in females but not in males
(ii) A gland that secretes hormone as well as digestive juice or enzyme
(iii) A gland associated with brain
(iv) A gland that is associated with kidneys
15 mL of water and 10 mL of sulphuric acid are to be mixed in a beaker.
(i) State the method that should be followed with reason.
(ii) What is this process called ?
Arvind visited his ancestral home in a remote village in mountains where the electric supply
has not reached yet. He saw the villagers using lantern. He met the village head and
explained him about the conversion of solar energy into electric energy. Village head called a
meeting of villagers and then gave the important task of bringing electricity to the village to
Arvind. Arvind happily agreed. Now answer the following questions :
(i) Name the device that converts solar energy into electric energy. Name the main
element used for making this device.
(ii) State two advantages of using this device.
(iii) State the values that prompted Arvind’s action.
Find the direction of magnetic field due to a current carrying circular coil held :
(i) vertically in North – South plane and an observer looking it from east sees the current
to flow in anticlockwise direction.
(ii) vertically in East – West plane and an observer looking it from south sees the current
to flow in anticlockwise direction.
(iii) horizontally and an observer looking at it from below sees current to flow in clockwise
direction.
State the rule to determine the direction of :
(i) the magnetic field produced around a current carrying conductor.
(ii) a force experienced by a straight current carrying conductor placed perpendicular to a
uniform magnetic field.
(iii) a current induced in a circuit by changing magnetic flux due to a bar magnet.
How will the strength of magnetic field due to a circular coil carrying current change at its
centre when the -(i) strength of current flowing in the coil is increased ?
(ii) number of turns in the coil is increased ?
(iii) radius of the coil is increased ?
Explain the following statements :
(a) Most metal oxides are insoluble in water but some of these dissolve in water. What are these
oxides and their solutions in water called?
(b) At ordinary temperature the surface of metals such as magnesium, aluminium and zinc etc. is
covered with a thin layer. What is the composition of this layer ? State its importance.
(c) Some alkali metals can be cut with a knife.
A gas is produced when Conc. H2SO4 is added to solid sodium chloride taken in a test tube.
The gas coming out of the delivery tube is passed over a dry blue litmus paper and then over
a moist blue litmus paper. What would you observe ? Explain reason with the help of a
chemical equation.
The potential difference between the two terminals of an electric iron is 220 V and the current
flowing through its element is 5.0 A. Calculate the resistance and wattage of the electric iron
What is an electric fuse? What is its role in electric circuits? Should it be placed on neutral
wire or on live wire? Justify your answer.
How does chemical coordination occur in plants ? Explain with the help of three examples
Explain the term „Nutrition‟. State the different modes of nutritio
You must have noticed that as you approached 10-12 years of age, many dramatic changes
appeared in your body. State reason.
