Gravitation – Questionbank with answer for CBSE Class 9 SA1

The following questions are for a quick revision of the chapter “Gravitation” for CBSE Class 9. There are many other questions which can be asked from the portion allotted for SA1, but will mainly based on these concepts. The questions are based on the bare essential concepts; the minimum level of learning expected from the [...]

Class XI Physics Revision Tests – Thermodynamics

PHYSICS TEST PAPER

THERMODYNAMICS

Max marks 35

Time 1 ½ hrs

Questions 1 to 5: 1 mark  each


Questions 6 to 10: 2 marks each


Questions 11 to 15: 3 marks each


Question 16: 5 marks


  1. What is an isochoric process?
  2. On what factors does the efficiency of a Carnot engine depend?
  3. State second law of thermodynamics. (Any one statement)
  4. State zeroth law of thermodynamics.
  5. What is a heat engine?
  6. State first law of thermodynamics and apply it to an isothermal process.
  7. Explain why a balloon is cooler after it bursts.
  8. What is a PV diagram? What does the area between the PV curve and the volume axis signify?
  9. State the conditions for two bodies to be in thermal equilibrium.
  10. State Carnot’s theorem and explain its significance.
  11. What is a cyclic process? Show that the work done in a cyclic process is equal to the area enclosed by the loop representing the cyclic process.
  12. Why gases have two principal specific heat capacities? Define them
  13. Why C > Cv? Prove that C – Cv = R
  14. Define the coefficient of performance of a heat pump. (refrigerator) and obtain a relation for it in terms of temperature T1 and T2
  15. A sample of gas (γ = 1.5) is compressed adiabatically from a volume of 1600 cm3 to 400 cm3.  If the initial pressure is 150 kPa, what is the final pressure and how much work is done on the gas in the process?
  16. Explain the construction and various operations involved in a Carnot’s heat engine with neat labeled diagram. Draw Carnot’s cycle and write expression for efficiency of a Carnot’s heat engine.

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Semiconductor Devices :: Some Questions for Practice

SEMICONDUCTORS

  • Draw a circuit diagram of OR gate.
  • What is a logic gate?
  • What types of charge-carriers are there in a n-type semi conductor?
  • Give the logical symbol of an AND gate. Mark the inputs and outputs.
  • Draw the logic symbol for a NAND gate.
  • Which biasing will make the resistance of p-n junction high?
  • Write the truth table for OR gate.
  • What is the change in the collector current, in a transistor of a.c. current gain 150, for a 100µA change in its base current?
  • When the voltage drop across a p-n junction diode is increased from 0.65V to 0.70V, the change in the diode current is 5mA. What is the dynamic resistance of the diode?
  • How does conductivity of a semiconductor change with rise in its temperature?
  • Draw a p-n junction with reverse bias.
  • What is the order of energy gap in a semiconductor?
  • Give the ratio of the number of holes and the number of conduction electrons in an intrinsic semiconductor.
  • In the given diagram, is the diode D forward or reversed biased?

  • Convert the number 39 into binary system.
  • Write the truth table for the combination of gates shown here.
  • How does the conductance of a semi conducting material change with rise in temperature?
  • Draw energy band diagram for a                                                                              (i) p- type extrinsic semiconductor                                                                                (ii) n-type extrinsic semiconductor                                                                         (iii) intrinsic semiconductors
  • Write the truth table for the following combination of gates:        
  • How does the collector current change in a junction transistor, if the base region has larger width?
  • How does the thickness of the depletion layer in a p-n junction vary with increase in reverse bias?
  • How does the energy gap in an intrinsic semiconductor vary, when doped with a pentavalent impurity?
  • Name the logic gate realized using p-n junction diodes in the given diagram. Give its logic symbol.
  • How does the energy gap in an intrinsic semiconductor vary, when doped with a trivalent impurity?
  • How does the width of the depletion region of a p-n junction vary, if the reverse bias applied to it increases?
  • What is  a solar cell? How does it work? Give its one use.
  • Frequency of input voltage to a half –wave rectifier is 50 Hz. What will be the frequency of the output voltage?
  • Draw the graph showing the variation of current with voltage for a p-n junction diode.
  • The output of an AND gate is connected to both the inputs of NAND gate. Draw the logic circuit of this combination of gates and write its truth table.
  • Derive a relationship between current gain of common base amplifier and current emitter amplifier.
  • Draw a circuit for p-n junction diode in forward bias. Sketch the voltage versus current graph for the same.
  • In the following diagrams, indicate which of the diodes are forward biased and which are reverse biased.   (i)                      (ii)                           (iii)                             (iv)
  • If the emitter and base of n-p-n transistor have same doping concentration, explain how will the collector and base-currents be affected?
  • What is an intrinsic semiconductor? How can you convert an intrinsic semiconductor into N-type extrinsic semiconductor?
  • Distinguish between n-type and p-type semiconductors on the basis of energy band diagram.
  • What is an ideal diode? Draw the output waveform across the load resistor R, if the input waveform is as shown in the figure.

  • Write the function of base region of a transistor. Why is this region made thin and slightly doped?
  • The output of a two input NAND gate is fed to a NOT gate. Write down the truth table for the final output of the combination.
  • ABOutput
    0

    0

    1

    1

    0

    1

    0

    1

    1

    1

    1

    0

  • The input resistance of a CE amplifier is 2K? and a current gain is 20. If the load resistance is 5 k?, Calculate: (i) the voltage gain of the amplifier and (ii) the trans-conductance of transistor used.
  • Draw the logic symbol of a 2-input NAND gate. Write down its truth table.
  • Draw the logic symbol of a 2-input NOR gate. Write down its truth table.
  • The following truth table gives the output of a                   2-input logic gate.
  • (i) Identify the logic gate used and draw its logic symbol.
  • (ii) If the output of  this gate is fed as input to aNOT gate, name the new logic gate so formed.
  • Give the logic symbol of AND gate. Explain with the help of circuit diagram, how this gate is realized in practice.
  • Give the logic symbol of OR gate. Explain with the help of circuit diagram, how this gate is realized in practice.
  • What is meant by the term, dopping of an intrinsic semiconductor? How does it affect the conductivity of a semiconductor?
  • If the output of a 2-input NAND gate is fed a the input to a NOT gate (i) name the new logic gate obtained and (ii) write down its truth table.
  • Explain briefly why the output and input signals of a common-emitter amplifier differ in phase by 1800.
  • In only one of the circuits given below the lamp L lights. Which circuit is it? Give reason for your answer.

(a)                                                                              (b)

  • In the circuit diagram given, a voltmeter V is connected across a lamp L. What changes would occur at lamp L and voltmeter V, if the resistor R is reduced in value? Give reason for your answer.
  • Draw the energy band diagram of an N-type semiconductor. How does the forbidden energy gap of an intrinsic semiconductor vary with increase in temperature?
  • If the emitter and base region of a transistor have same doping concentration, state how (i) collector current and (ii) d.c. current gain of the transistor will change.
  • Determine the currents through the resistance ‘R’ of the circuits (i) and (ii), when similar diodes D1 and D2 are connected as shown below.
  • Pure silicon at 300 K has equal electron and hole concentrations of 1.5 x 1016/m3. Doping by Indium    increases the hole concentration to 4.5 x 1022/m3. Calculate the new electron concentration in the doped silicon.
  • Distinguish between n-type and p-type semiconductors on the basis of energy band diagram.
  • The output of an OR gate is connected to both the inputs of a NAND gate. Draw the logic circuit of this combination of gates and write its truth table.
  • Draw a circuit diagram to show the biasing of a n-p-n transistor. Explain the transistor action.
  • Define the terms ‘potential barrier’ and ‘depletion region’ for a p-n junction diode. State how the thickness of depletion region will change when the p.n junction diode is (i) forward biased. (ii) reverse biased.
  • With the help of labelled circuit diagram, explain the rectification action of a full wave rectifier.
  • If the base region of a transistor is made large, as compared to a usual transistor, how does it affect (i) the collector current, and (ii)current gain of this transistor? What is the phase difference between the input and output signals of a common emitter amplifier?
  • Explain how the depletion layer and barrier potential are formed in a p-n junction diode.
  • The output of an OR gate is connected to both the inputs of a NAND gate. Draw the logic circuit of this combination of gates and write its truth table.
  • Symbolically represent a pnp transistor. Show the biasing of a pnp transistor and explain the transistor action.
  • Distinguish between conductors, semiconductors and insulators on the basis of band theory of solids.
  • Draw the circuit diagram of a common-emitter amplifier, with appropriate baising. What is the phase difference between the input and output signals ?State two reasons why a common-emitter-amplifier is preferred to a common base amplifier.,
  • Draw the energy band diagram of a p-type semiconductor. Deduce an expression for the conductivity of a p-type semiconductor.
  • Draw a circuit diagram to obtain the characteristics of a npn transistor in emitter configuration. Describe    how you will obtain input and output characteristics. Give shape of the curves.
  • Draw the circuit diagram of a full-wave rectifier and briefly explain its working principle.
  • Identify the logic gates marked X and Y in the figure given. Write the truth-table to find the. output at Z for all values of A and B.
  • Explain how the depletion region and barrier potential are formed in a p-n junction diode.
  • Identify the logic gates marked X and Y in the figure given. Write the truth-table to find the. output at Z for all values of A and B.
  • With a circuit diagram, briefly explain how a zener diode can be used as a voltage regulator.
  • In the figure given below is (i) the emitter, and (ii) the collector forward or reverse biased? With the help of a circuit diagram, explain the action of a n-p-n transistor.

  • Explain how an intrinsic semiconductor can be converted into (i)n-type and             (ii) p-type semiconductor. Give one example of each and their energy band diagrams.
  • Draw the circuit diagram to show the use of a transistor as an oscillator. State how the positive feedback is provided in the circuit.
  • In the figure below, circuit symbol of a logic gate and two input waveforms ‘A’ and ‘B’ are shown.


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