Advertisements
Advertisements
प्रश्न
A battery of e.m.f. 15 V and internal resistance 2 `Omega` is connected to tvvo resistors of 4 ohm and 6 ohm joined.
(i) In series,
(ii) In para 1 lel. Find in each case the electrica I energy spent per minute in 6 ohm resistor.
Advertisements
उत्तर
Given, emf= 15 V, internal resistance, r= 2 `Omega`
(i) Total resistance of given resistors in series, Rs = 4 + 6 = 10 `Omega`
Now, current through series combination on, Is = `"emf"/("R"_"s" + "r") = 15/(10 + 2) = 15/12` = 1.25 A
In series, the same current will pass through each resistor
.·. electrical energy spent per minute in the 6`Omega` resistor, Hs = I2 (R) t = (1.25)2 (6) (60) = 562.5 J
(ii) Total resistance of given resistors in parallel, RP = `(1/4 + 1/6) ^-1 = 2.4 Omega`
Current in parallel circuit, I = `15/(2.4 + 20) = 3.4 "A"`
In parallel, each resistor is connected across the same voltage, say V.
Then, V = e - Ir= 15 - (3.4 x 2) = 8.18 volt
:. electrical energy spent per minute in the 6Ω resistor, Hp = `"V"^2/"R" t = (8.18)^2/6 xx 60 `= 669.1 J
APPEARS IN
संबंधित प्रश्न
What are the advantages of connecting electrical devices in parallel with the battery instead of connecting them in series?
A wire that has resistance R is cut into two equal pieces. The two parts are joined in parallel. What is the resistance of the combination?
An electric heater which is connected to a 220 V supply line has two resistance coils A and B of 24 Ω resistance each. These coils can be used separately (one at a time), in series or in parallel. Calculate the current drawn when:
(a) only one coil A is used.
(b) coils A and B are used in series.
(c) coils A and B are uses in parallel.
Show with the help of diagrams, how you would connect three resistors each of resistance 6 Ω, so that the combination has resistance of (i) 9 Ω (ii) 4 Ω.
A resistor of 8 ohms is connected in parallel with another resistor X. The resultant resistance of the combination is 4.8 ohms. What is the value of the resistor X?
A particular resistance wire has a resistance of 3 ohm per meter. Find the total resistance of three lengths of this wire each 1.5 m long, joined in parallel.
The equivalent resistance of a parallel combination of two resistors of 30 Ω and 60 Ω is ______________.
Calculate equivalent resistance in the following cases:
Three resistors of 6Ω, 4Ω and 4Ω are connected together so that the total resistance is 8Ω. Draw a diagram to show this arrangement and give reason to justify your answer.
Two V-I graphs A and B for series and parallel combinations of two resistors are as shown. Giving reason state which graph shows (a) series, (b) parallel combination of the resistors.
