Page 1 : 4) 08:57 fae + Ok 42% 32% >), , € = 28th-physics-1-.. [( @ :, , 10ne mark questions., 1. Electric current originates from which part of a conductor? (), , {a}nucleus(b) entire atomas a single atom (c) positively charged protons (4) negatively charged electrons, 2. The resistance of the wire varies inversely as: (), , {2) Area of cross section (b) resistivity (c) length (4) temperature, , 3. Ohm's law states which relationship between electrical quantities? (), , (2) Potential difference = Current times resistance, , {b) Potential dference = Current divides resistance, , {c) Potential difference = Charge divides current, , (4) Potential difference = Charge times resistance, , 4, V- graph for two wires A and 8 are shown in the figure. If both wires are of same length and same, , thickness, which of the two is made of a material of high resistivity? Give |ustification for your answer., , 5. A ven length of a wire is doubled on itself and this process is repeated once again. By what factor does, the resistance of the wire change?, , Three mark questions,, , 6, (i) The wattage of a bulb is 24 W when itis connected to.a 12 V battery. Calculate its effective wattage if, operates on a 6 V battery (Neglect the change in resistance due to unequal heating ofthe filament in the, two cases}., , {i piece of wire of resistance 20 0 is drawn out so that its length is increased to twice its original length., , Calculate the resistance of the wire in the new Situation., , 74) Find the current drawn from the battery by the network of four resistors Shown in the figure., , 1 —_______, {i) Define 1 volt. Express it in terms of SI unit of work and charge calculate the amount of energy, ‘consumed in carrying a charge of 1 coulomb through a battery of 3 V., £8. () An electric bulb of resistance 2000 draws a current of 1 Ampere. Calculate the power of the bulb the, potential difference at its ends and the energy in kWh consumed burning It for Sh., {l) Draw a schematic diagrams of an electric circuit comprising of 3 cells and an electric bulb, ammeter,, plug-key in the ON mode and another with same components but with two bulbs in parallel and 2, voltmeter across the combination., 9. A bulb is rated at 330V- 110W. What do you think is its resistance? Three such bulbs burn for Shrs at a, stretch. What is the energy consumed? Calculate the cost in rupees ifthe rate is 70 paise per unit?, 10. You take two resistors of resistance 2R and 3R and connect them in parallel in an electric circuit., Calculate the ratio of the electrical power consumed by 2R and 38?, , Live mark questions., 11. (9 A torch bulb is rated at 3V and 600mA. Calculate it's (a) Power, (b) Resistance, (c) Energy consumed, iit lighted for 4 Hrs., , (i) Explain the relation between the direction of flow of electrons andthe direction of conventional current, across a conductor?, , 12, ()An electric iron consumes energy at rate of 420w when heating s at maximum rate and 180 w when, heating is at minimum. The voltage i 220V What isthe current and resistant in each case?, , (i) Out of 60 W and 40 W tarps, which one has a higher electrical resistance when in use?, , 13. () Define resistance and resistivity and also give the relation between them. Explain the dependence of, resistance on temperature., , (li) Calculate the potential difference between the two terminals of a battery if 100 joules of work is, required to transfer 20 coulombs of charge from one terminal of the battery to the other., , 14, Derive the expression for the heat produced due toa current ‘I’ flowing for a time interval ‘t’ through a, resistor‘ having a potential difference ‘V" across its ends. With which name is the relation known? How, ‘much heat wil an instrument of 1217 produce in one minute if its connected toa battery of 12V?, , 15. Two lamps, one rated 80 W at 220 V andthe other 100 W at 220 V, are connected in paralle! to the, electric supply at 220 V. (a) Draw a circuit diagram to show the connections, (b) Calculate the current, <rawn trom the electric supply, (c)Calculate the total energy consumed by the two lamps together when, they operate for one hour