Advertisements
Advertisements
प्रश्न
If the length of a wire is doubled by taking more of wire, what happens to its resistance?
Advertisements
उत्तर
The area of cross-section of the wire, A = πr2
APPEARS IN
संबंधित प्रश्न
In series combination which remains constant?
(a) Voltage
(b) Current
(c) Both current and voltage
(d) Both are variables
A piece of wire of resistance R is cut into five equal parts. These parts are then connected in parallel. If the equivalent resistance of this combination is R’, then the ratio `"R"/"R'"` is ______.
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.
Find the equivalent resistance between points A and B
When a 4 Ω resistor is connected across the terminals of a 12 V battery, the number of coulombs passing through the resistor per second is:
(a) 0.3
(b) 3
(c) 4
(d) 12
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
Draw a V-I graph for a conductor at two different temperatures. What conclusion do you draw from your graph for the variation of resistance of conductor with temperature?
Name the following substance showing low resistivity.
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.
Define the term resistivity and state its S.I. unit. Which will have higher resistivity a conductor or an insulator.
State and explain the laws of resistance.
Calculate the equivalent resistance between the points A and B for the following combination of resistors:
Calculate the equivalent resistance between P and Q from the following diagram:
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.
A metal wire of resistance 6 Ω is stretched so that its length is increased to twice its original length. Calculate its new resistance.
The resistance of two resistors joined in series is 8Ω and in parallel is 1.5Ω. Find the value of the two resistances.
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?
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:
