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What Happens to the Resistivity of Semi-conductor with the Increase of Temperature? - Physics

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Question

What happens to the resistivity of semiconductor with the increase of temperature?

Solution

The resistivity of a semiconductor decreases with increase in temperature

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Internal Resistance of a Cell
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2014-2015 (March) Science Paper 1

RELATED QUESTIONS

Name two factors on which the internal resistance of a cell depends and state how does it depend on the factors stated by you.


Explain why the p.d across the terminals of a cell is more in an open circuit and reduced in a closed circuit. 


A cell is used to send current to an external circuit.

  1. How does the voltage across its terminals compare with its e.m.f.?
  2. Under what condition is the e.m.f. of a cell equal to its terminal voltage? 

The diagram below in Fig. 8.40 shows a cell of e.m.f. ε = 2 volt and internal resistance r = 1 ohm to an external resistance R = 4 ohm. The ammeter A measures the current in the circuit and the
voltmeter V measures the terminal voltage across the cell. What will be the readings of the ammeter and voltmeter when (i) the key K is open, (ii) the key K is closed. 

  


A cell of e.m.f. 2 V and internal resistance 1.2 Ω is connected to an ammeter of resistance 0.8 Ω and two resistors of 4.5 Ω and 9 Ω as shown in following figure.

Find:

  1. The reading of the ammeter,
  2. The potential difference across the terminals of the cells, and
  3. The potential difference across the 4.5 Ω resistor.

A cell of emf. 1.5 V and internal resistance 10 ohms is connected to a resistor of 5 ohms, with an ammeter in series see fig.. What is the reading of the ammeter?


Four cells each of e.m.f. 2V and internal resistance 0.1 Ω are connected in series to an ammeter of negligible resistance, a 1.6 Ω resistor and an unknown resistor R1. The current in the circuit is 2A. Draw a labelled diagram and calculate:

(i) Total resistance of the circuit,
(ii) Total e.m.f.
(iii) The value of R1 and
(iv) The p.d. across R1.


A cell supplies a current of 0.6 A through a 2Ω coil and a current of 0.3 A through on 8Ω coil. Calculate the e.m.f and internal resistance of the cell.


Study the diagram:

  1. Calculate the total resistance of the circuit.
  2. Calculate the current drawn from the cell.
  3. State whether the current through 10 Ω resistor is greater than, less than or equal to the current through the 12 Ω resistor.

The diagram in Figure shows a cell of e.m.f. ε = 4 volt and internal resistance r = 2 ohm connected to an external resistance R = 8 ohm. The ammeter A measures the current in the circuit and the voltmeter V measures the terminal voltage across the cell. What will be the readings of the ammeter and voltmeter when

  1. the key K is open, and
  2. the key K is closed


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