Advertisements
Advertisements
Question
How does the presence of impurities in a metal affect its resistance?
Advertisements
Solution
The presence of impurities in a metal increases its resistivity (also resistance) and it does not undergo oxidation easily even at a high temperature.
APPEARS IN
RELATED QUESTIONS
Find the expression for the resistors connected in series and write the two characteristics of it. (Draw figure).
Find the expression for resistors connected in series.
The V-I graph for a series combination and for a parallel combination of two resistors is shown in the figure below. Which of the two A or B. represents the parallel combination? Give reasons for your answer.
The substance having infinitely high electrical resistance is called:
(a) conductor
(b) resistor
(c) superconductor
(d) insulator
Give one example to show how the resistance depends on the nature of material of the conductor.
What possible values of resultant resistance one can get by combining two resistances, one of value 2 ohm and the other 6 ohm?
State how are the two resistors joined with a battery when equivalent resistance is more than either of the two resistances.
How will you oonnect five resistors, each of the value one ohm, to obtain an equivalent resistance of 0.2 `Omega`
Choose the correct alternative and rewrite the following:
You are given three equal resistances. In how many combinations can they are arranged?
When do you say that the resistors are connected in this way? Draw a circuit diagram.
State expression for Cells connected in parallel.
State a relation between electrical power, resistance and potential difference in an electrical circuit.
Illustrate-combination of cells e.g., three cells, in parallel, explaining the combination briefly. Obtain an expression for current ‘i’ in the combination.
The resistance of the hot filament of the bulb is about 10 times the cold resistance. What will be the resistance of 100 W-220 V lamps, when not in use?
What is the maximum resistance which can be made using five resistors each of `1/5` W?
If the current I through a resistor is increased by 100% (assume that temperature remains unchanged), the increase in power dissipated will be:
When a 4 Ω resistor is connected across the terminals of a 2 V battery, the number of coulombs passing through the resistor per second is:
