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How Does the Presence of Impurities in a Metal Affect Its Resistance? - Science

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प्रश्न

How does the presence of impurities in a metal affect its resistance?

उत्तर

 The presence of impurities in a metal increases its resistivity (also resistance) and it does not undergo oxidation easily even at a high temperature.

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अध्याय 1: Electricity - Exercise 4

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लखमीर सिंग Physics (Science) [English] Class 10
अध्याय 1 Electricity
Exercise 4 | Q 12.2

संबंधित प्रश्न

Two resistors of 4Ω and 6 Ω are connected in parallel to a cell to draw 0.5 A current from the cell.
(i) Draw a labelled circuit diagram showing the above arrangement.
(ii) Calculate the current in each resistor. What is an Ohmic resistor?


You are supplied with a number of 100 Ω resistors. How could you combine some of these resistors to make a 250 Ω resistor?


A graph is plotted taking p.d. along y-axis and electric current along x-axis. Name the physical quantity that represents the slope of this graph (Fig.).


Three resistors of 6.0 Ω, 2.0 Ω and 4.0 Ω are joined to an ammeter A and a cell of emf 6.0 V as shown in the following figure. Calculate :

  1. the effective resistance of the circuit.
  2. the reading of ammeter.


Choose the correct alternative and rewrite the following sentence.

If three resistors 2 ohms, 3 ohms and 4 ohms are connected in series, then the effective resistance in the circuit will be _______ ohms.


Answer the following question.
While studying the dependence of potential difference ( V) across a resistor on the current (I) passing through it, in order to determine the resistance of the resistor, a student took 5 readings for different values of current and plotted a graph between V and t. He got a straight line graph passing through the origin. What does the straight-line signify? Write the method of determining the resistance of the resister using this graph. 


The voltage applied to a given rheostat is made four times its initial value. By what factor will be resistance of the rheostat change?


Two lamps of resistance 30Ω and 20Ω respectively are connected in series in a 110V circuit. Calculate:
(i) the total resistance in the circuit
(ii) the current in the circuit, and
(iii) the voltage drop across each lamp.


Two wires of same material and same lengths have radii in the ratio of 2 : 3, Compare their resistances.


The resistance of two resistors joined in series is 8Ω and in parallel is 1.5Ω. Find the value of the two resistances.


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