Science
(a) Define electric power. Express it in terms of potential difference (V) and resistance (R).
(b) An electric oven is designed to work on the mains voltage of 220 V. This oven consumes 11 units of electrical energy in 5 hours. Calculate :
- power rating of the oven
- current drawn by the oven
- resistance of the oven when it is red hot
Related Questions
(a) Name three techniques/devices used by human females to avoid pregnancy. Mention the side effects caused by each.
(b) What will happen if in a human female
- fertilisation takes place,
- an egg is not fertilised?
(a) Draw a diagram showing spore formation in Rhizopus and label the (i) reproductive and (ii) non-reproductive parts. Why does Rhizopus not multiply on a dry slice of bread?
(b) Name and explain the process by which reproduction takes place in Hydra.
The metals produced by various reduction processes are not very pure. They contain impurities, which must be removed to obtain pure metals. The most widely used method for refining impure metals is electrolytic refining.
(a) What is the cathode and anode made of in the refining of copper by this process ?
(b) Name the solution used in the above process and write its formula.
(c) How copper gets refined when electric current is passed in the electrolytic cell?
OR
(c) You have two beakers 'A' and 'B' containing copper sulphate solution. What would you observe after about 2 hours if you dip a strip of zinc in beaker 'A' and a strip of silver in beaker ‘B’? Give reason for your observations in each case.