In a tabular form write the colours of the following indicators in presence of acid and
base :
State Joule’s law of heating. On what factors the heat produced in a resistor depends
(a) Explain why there are two separate circuits one for high power rating appliances and
the other for low power rating appliances.
(b) A domestic circuit has a 5 A fuse. How many bulbs of rating 100 W; 220 V can be
safely used in this circuit ? Justify your answer.
What is meant by the term magnetic field ? Draw the pattern of magnetic field lines due to a
current carrying solenoid. How can the strength of this magnetic field be increased ? Explain.
List two properties of magnetic field lines
(a) Write the chemical formula of hydrated copper sulphate and anhydrous copper
sulphate. Giving an activity illustrate how these two are inter convertible.
(b) Write chemical names and formulae of Plaster of Paris and Gypsom
a) Write electron dot structure for chlorine (At. No. 17) and calcium (At. No. 20). Show
the formation of calcium chloride by the transfer of electrons.
(b) Identify the nature of the above compound and explain three physical properties of
such compounds.
(a) Write three main functions of the nervous system.
(b) In the absence of muscle cells, how do plant cells show movement ?
A student fixes a sheet of white paper on a drawing board. He places a bar magnet in the centre of it. He sprinkles some iron filings uniformly around the bar magnet. Then he taps
the board gently.
Now answer the following questions :
(i) What does the student observe ? Draw a diagram to illustrate your answer.
(ii) Why do the iron filings arrange in such a pattern ?
(iii) What does the crowding of the iron filings at the ends of the magnet indicate ?
(a) Explain how the separation of oxygenated and deoxygenated blood is useful in
humans
(b) Why is double circulation of blood necessary in humans
Biogas is an excellent fuel. Justify the statement by giving two reasons. Mention the mass
constituent of biogas along with its percentage.
