Heating & Chemical Effect of Current
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Questions and Answers

What is the thermoelectric potential developed by a single thermocouple when the temperature difference between the hot and cold junctions is 20 K?

  • 40 μV (correct)
  • 20 μV
  • 10 μV
  • 80 μV

    • What occurs at the junction where current flows from Cu to Fe?

  • Energy is released
  • Energy is absorbed (correct)
  • No energy transfer occurs
  • The temperature remains constant

    • What is the total emf developed by a thermopile consisting of 150 thermocouples in series when the temperature difference between the hot and cold junctions is 20 K?

  • 80 mV
  • 120 mV (correct)
  • 144 mV
  • 150 mV

    • What is the relationship between the heat absorbed or liberated at a junction and the charge passing through it?

    <p>H ∝ Q</p> Signup and view all the answers

    What is the process of decomposition of an electrolyte solution into ions on passing an electric current through it?

    <p>Electrolysis</p> Signup and view all the answers

    What is the unit of the Peltier coefficient?

    <p>J/C</p> Signup and view all the answers

    What is the term for the ability of an electric current to produce or speed up chemical change?

    <p>Chemical effect</p> Signup and view all the answers

    What determines the value of the Peltier coefficient?

    <p>Both the temperature of the junction and the difference in electron density of the two metals</p> Signup and view all the answers

    What is the term for liquids that do not allow current to pass through them?

    <p>Insulators</p> Signup and view all the answers

    What is the relationship between the Peltier coefficient and the absolute temperature?

    <p>π = T × S</p> Signup and view all the answers

    What is the graph of thermo electric power in a thermocouple?

    <p>A straight line with a positive slope</p> Signup and view all the answers

    What happens when a positive charge flows from a high potential to a low potential?

    <p>Energy is released</p> Signup and view all the answers

    What is the polarity of the contact potential at each junction in an iron-copper thermocouple?

    <p>Iron is at higher potential</p> Signup and view all the answers

    What happens at the junction in a thermocouple when current flows from iron to copper?

    <p>Heat is evolved</p> Signup and view all the answers

    What is the Peltier effect?

    <p>Heat evolved or absorbed at a junction of two different metals when a current is passed through it</p> Signup and view all the answers

    What is the primary purpose of electroplating?

    <p>To make the base metal look more attractive</p> Signup and view all the answers

    What is the role of the anode in electrolysis?

    <p>It is the site of oxidation</p> Signup and view all the answers

    What is the equivalent weight of an element?

    <p>The ratio of the atomic weight of an element to its valency</p> Signup and view all the answers

    What is the purpose of a voltameter?

    <p>To carry out electrolysis</p> Signup and view all the answers

    What is the term for the decomposition of an electrolyte solution into ions on passing an electric current through it?

    <p>Electrolysis</p> Signup and view all the answers

    What is the volume ratio of hydrogen and oxygen liberated during electrolysis of water?

    <p>2:1</p> Signup and view all the answers

    What is the relationship between the mass of substance deposited at the cathode and the quantity of electricity passed through the electrolyte?

    <p>Directly proportional</p> Signup and view all the answers

    What is the electrochemical equivalent of a substance?

    <p>The mass of substance deposited at the cathode when one coulomb of charge passes through the electrolyte</p> Signup and view all the answers

    What occurs at the cathode during electrolysis of water?

    <p>Hydrogen gas is collected</p> Signup and view all the answers

    What is the role of the anode in electrolysis of water?

    <p>To collect oxygen gas</p> Signup and view all the answers

    What is the primary reason for the wastage of Zn in a voltaic cell?

    <p>Local electric currents due to impurities on the surface of the Zn rod</p> Signup and view all the answers

    What is the purpose of amalgamating the Zn rod with mercury?

    <p>To prevent local electric currents and wastage of Zn</p> Signup and view all the answers

    What is the effect of polarisation on the voltaic cell?

    <p>It weakens the action of the cell</p> Signup and view all the answers

    What is the endpoint voltage of a dry cell?

    <p>0.8 V</p> Signup and view all the answers

    What is the reason electrolytes are less conducting than metallic conductors?

    <p>Ions are heavier than electrons</p> Signup and view all the answers

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