CBSE Physics Thermal and Chemical Effect Expected Questions : Unit III
Short Answer Type Questions
Q. 1. What are charge carriers ? What are they called in electrolysis phenomenon ?
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Q. 2. In what respects does a wire carrying a current differ from a wire carrying no current ?
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Q. 3. Why is the heat produced in a current carrying conductor ?
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Q. 4. The filament of the bulb is heated up when the current passes through the bulb but the wire connected to it is not heated much. Explain why ?
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Q. 5. Two lamps have filaments of same material and is of same length. If first bulb is of 75 W rating and the second one is 150 W, which has more thick wire.
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Q. 6. A toaster produces more heat than a light bulb when they are connected in parallel. Which one has greater resistance ?
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Q. 7. A 50W bulb is connected in (i) series ; (ii) parallel with a room heater is connected across that mains. If 50 W bulb is now replaced by 150 W bulb in each of the two cases, will the heat produced by heater be smaller, remain the same or be larger.
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Q. 8. Two bulbs are 100 W and 50 W and are put in series. Each bulb is rated 200 V and the series combination is put across 220 V mains. Comment unsn the result.
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Q. 9. Molten sodium chloride conducts electricity while hydrogen chloride below its boiling point is non-conducting liquid. Why ? The solution of HC1 in water is however very strongly conducting. Why ?
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Q. 10. What are the carriers of current in (i) copper electrodes in CuSO4 solution ; (ii) silver electrodes in AgNO3 solution.
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Q. 11. What are strong and weak electrolytes ?
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Q. 12. Why some non-ionic (in solid state) covalent salts (Al2 Cl6) become conducting when dissolved in water ?
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Q. 13. What is the time for which a current if 10 A pass through a solution of zinc sulphate to deposite 5 gram of zinc ? E.C.E. of zinc = 0 000338 g C-1
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Q. 14. It is desired to deposite 0.5 kg of silver per hour on the cathode of a silver voltameter whose resistance is 2 m Ω. How much P.D. must be maintained between the plates of the voltameter during electrolysis ? Use the known value of Faraday’s constant F - 96,500 C mol-1. Relative atomic mass of silver is 108.
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Q. 15. During electrolysis in silver voltameter, is the rate of deposite of silver on cathode equal to the rate of dissolving of silver on the anode in the solution ?
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Q. 16. In silver voltameter, are the drift speeds of Ag+ and NO3 ions equal to each other and also to the drift speed of electrons in the external circuit ?
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Q. 17. In silver voltameter, is the total current in voltameter equal to (i) the current of Ag+ions or (si) the current due to NO3 ion or (iii) the sum of currents due to both Ag+ and NO3 ions ?
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Q. 18. Why do electrolytes possess less conductivity ?
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