Advertisements
Advertisements
प्रश्न
Find the expression for resistors connected in series.
उत्तर
When two or more resistors are joined from end to end, the resistances are connected in series.
The current in series remains the same across all the resistors.
The potential difference is the sum of potential differences across all the individual resistors.
V = V1 + V2 + V3 … (1)
Let I be the current in the circuit.
On applying Ohm’s law to the entire circuit, we get
V = IRs … (2)
Here, Rs is the combined resistance of the circuit.
Now, applying Ohm’s law to individual resistances, we get
V1 = IR1
V2 = IR2
V3 = IR3 ......(3)
From equations (1), (2) and (3), we get
IRs = IR1 + IR2 + IR3
∴ Rs = R1 + R2 + R3
Here, Rs is the resultant resistance. Thus, the resultant resistance of a series combination of resistors is the sum of individual resistances.
The resultant resistance is greater than all the resistances.
APPEARS IN
संबंधित प्रश्न
In series combination which remains constant?
(a) Voltage
(b) Current
(c) Both current and voltage
(d) Both are variables
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
A battery of 9 V is connected in series with resistors of 0.2 Ω, 0.3 Ω, 0.4 Ω, 0.5 Ω and 12 Ω, respectively. How much current would flow through the 12 Ω resistor?
How does the presence of impurities in a metal affect its resistance?
Give one example to show how the resistance depends on the nature of material of the conductor.
Give the law of combination of resistances in series.
If five resistances, each of value 0.2 ohm, are connected in series, what will be the resultant resistance?
V = IRTwo resistances X and Y are connected turn by turn : (i) in parallel, and (ii) series. In which case the resultant resistance will be less than either of the individual resistances?R = R1+ R2+ R3
Name a substance of which the resistance remains almost unchanged by the increase in temperature.
Name the following substances:
(i) Showing low resistivity,
(ii) Showing very high resistivity,
(iii) Showing moderate resistivity.
Calculate the equivalent resistance of the following combination of resistor r1, r2, r3, and r4
Choose the correct option from given alternative:
Two bulbs of 100 W and 40 W are connected in series. The current through the 100 W bulb is 1A. The current through the 40W bulb will be:
State and explain the laws of resistance.
You are provided with three resistors of resistance 1.0 Ω, 2.0 Ω and 3.0 Ω How would you connect them to obtain the total effective resistance 1.5 Ω? Draw diagram of the arrangement and check it by calculations.
Two wires of same material and same lengths have radii in the ratio of 2 : 3, Compare their 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?
