Advertisements
Advertisements
Question
How does the resistance of a pure metal change if its temperature decreases?
Advertisements
Solution
The resistance of all pure metals increases on raising the temperature and decreases on lowering the temperature. Therefore, the resistance of a pure metal will decrease on decreasing the temperature.
APPEARS IN
RELATED QUESTIONS
If the equivalent resistance is to be increased, then the number of resistances should be connected in
- Series
- Parallel
- Mixed arrangement
- None of the above
Judge the equivalent resistance when the following are connected in parallel − (a) 1 Ω and 106Ω, (b) 1 Ω and 103Ω and 106Ω.
Write any two characteristics of a series combination of resistors.
If the length of a wire is doubled by taking more of wire, what happens to its resistance?
Give one example to show how the resistance depends on the nature of material of the conductor.
If five resistances, each of value 0.2 ohm, are connected in series, what will be the resultant resistance?
If two resistors of 25 Ω and 15 Ω are joined together in series and then placed in parallel with a 40 Ω resistor, the effective resistance of the combination is :
(a) 0.1 Ω
(b) 10 Ω
(c) 20 Ω
(d)40 Ω
You are supplied with a number of 100 Ω resistors. How could you combine some of these resistors to make a 250 Ω resistor?
State how are the two resistors joined with a battery when equivalent resistance is more than either of the two resistances.
What do you mean by power rating of an electrical appliance? How do you use it to calculate
(a) the resistance of the appliance and
(b) the safe limit of the current in it, while in use?
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.
Name the material of wire used for making standard resistances. Give a reason.
Define the term resistivity and state its S.I. unit. Which will have higher resistivity a conductor or an insulator.
What is the equivalent resistance between the points X and Y for the given network?
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.
Calculate the value of the resistance which must be connected to a 15 ohm resistance to provide on effective resistance of 6 ohm.
A metal wire of resistance 6 Ω is stretched so that its length is increased to twice its original length. Calculate its new resistance.
