Advertisements
Advertisements
प्रश्न
Find the expression for the resistors connected in series and write the two characteristics of it. (Draw figure).
Advertisements
उत्तर
Expression for the resistors in series:
R1, R2 and R3 are the three resistors connected in series between points C and D as shown in the figure above. I is the current and V is the PD across points
C and D.
Rs is the effective resistance in a circuit, and V1, V2 and V3 are the potentials across the three resistors such that
V = V1 + V2 + V3 ---- (1)
Using Ohm’s law, the total potential difference
V = I Rs
and V1 = IR1, V2 = IR2 and V3 = IR3
Substituting these values in Equation 1, we get
IRs = IR1 + IR2 + IR3
∴ Rs = R1 + R2 + R3
For n number of resistors connected in series,
Rs = R1 + R2 + R3 + R4 + ----- + Rn
Characteristics of a series combination of resistors:
a) The same current flows through each resistor.
b) The effective resistance of the combination is greater than any of the resistances in the combination.
c) The effective resistance of the combination is equal to the sum of individual resistors.
APPEARS IN
संबंधित प्रश्न
Judge the equivalent resistance when the following are connected in parallel − (a) 1 Ω and 106Ω, (b) 1 Ω and 103Ω and 106Ω.
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 ______.
Find the equivalent resistance between points A and B.
Find the equivalent resistance between points A and B
The substance having infinitely high electrical resistance is called:
(a) conductor
(b) resistor
(c) superconductor
(d) insulator
If the length of a wire is doubled by taking more of wire, what happens to its resistance?
You are supplied with a number of 100 Ω resistors. How could you combine some of these resistors to make a 250 Ω resistor?
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?
State the order of resistivity of (i) a metal, (ii) a semiconductor and (iii) an insulator.
Name a substance of which the resistance remains almost unchanged by the increase in temperature.
State how are the two resistors joined with a battery when equivalent resistance is more than either of the two resistances.
In series combination of resistances ______.
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.).
Name the material of wire used for making standard resistances. Give a reason.
Write an expression for the resistance of a conducting wire in terms of its length and area of cross-section.
Six resistances are connected together as shown in the figure. Calculate the equivalent resistance between points A and B.
Illustrate-combination of cells e.g., three cells, in series, explaining the combination briefly. Obtain an expression for current ‘i’ in the combination.
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.
Show how you would connect three resistors, each of resistance 6 Ω, so that the combination has a resistance of 4 Ω.
