Thursday, November 25, 2010

SRIRAM

 2.Current Electricity 1. State Ohm's law 2 State faraday's laws of electrolysis 3 Write any three applications of superconductors 4 A manganin wire of length 2 m has a diameter of 0.4 mm with a resistance of 70 Ώ Find the resistivity of the material. 5. State Kirchoff's (i) current law and (ii)voltage law 6 State kirchoff's voltage law. 7 Define mobility of electrons . Give its unit 8 Define drift velocity. 9 The resistance of a platinum wire at 0c is 4Ω what will be the resistance of the wire at 100c if the temperature coefficient of resistance of platinum is 0.0038/c? Distinguish between electromotive force and potential difference 11 The resistance of a nichrome wire at 0c is 10Ω it is temperature coefficient of resistance is 0.004/c. find its resistance at boiling point of water. Comment on the result. .12 Define temperature coefficient of resistance. 13 Distinguish between electric power and electric energy 14 An iron box of 400 w power is used daily for 30 minutes. If the cost per unit is 75 paise . find the weekly expense on using the iron box. 15 What are the applications of secondary cells 16 Two wires of same material and length have resistance 5Ω and 10Ω respectively. Find the ratio of radii of the two wires. 17 State Kirchhoff's second law for electrical network.