Advertisements
Advertisements
प्रश्न
How does the presence of impurities in a metal affect its resistance?
Advertisements
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.
APPEARS IN
संबंधित प्रश्न
An electrical appliance has a resistance of 25 Ω. When this electrical appliance is connected to a 230 V supply line, the current passing through it will be:
(a) 0.92 A
(b) 2.9 A
(c) 9.2 A
(d) 92 A
Name the material which is the best conductor of electricity.
Give the law of combination of resistances in series.
What is (a) highest, and (b)Ω lowest, resistance which can be obtained by combining four resistors having the following resistances?
4 Ω, 8 Ω, 12 Ω, 24 Ω
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.
Two bulbs of 100 W and 40 W are connected in series. The current through the 100 W bulb is 1 A. The current through the 40 W bulb will be ______.
A given metallic wire of resistance R is doubled on itself. What will be its new resistance?
Why are thick copper wires used as connecting wires?
Write an expression for the resistance of a conducting wire in terms of its length and area of cross-section.
State expression for Resistance connected in series.
What is a resistance? Define it with respect to Ohm’s law,
Three resistors of 6Ω, 3Ω and 2Ω are connected together so that their total resistance is greater than 6Ω but less than 8Ω Draw a diagram to show this arrangement and calculate its total resistance.
2Ω resistor A, 1Ω resistor B and 4Ω resistor C are connected in parallel. The combination is connected across a 2V battery of negligible resistance. Draw the diagram of the arrangement and calculate:
(i) The current in each resistor A and C,
(ii) The current through battery.
Two resistors of 4Ω and 6Ω are connected in parallel to a cell to draw 0.5 A current from the cell.
Draw a labelled circuit diagram showing the above arrangement.
A metal wire of resistance 6 Ω is stretched so that its length is increased to twice its original length. Calculate its new resistance.
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:
Show how you would connect three resistors, each of resistance 6 Ω, so that the combination has a resistance of 4 Ω.
