Advertisements
Advertisements
Question
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
Solution
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
RELATED QUESTIONS
In the circuit given below:
(a) What is the combined resistance?
(b) What is the p.d. across the combined resistor?
(c) What is the p.d. across the 3 Ω resistor?
(d) What is the current in the 3 Ω resistor?
(e) What is the current in the 6 Ω resistor?
In the diagram shown below, the cell and the ammeter both have negligible resistance. The resistor are identical.
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.
You are given three resistances of 1, 2 and 3 ohms. Shows by diagrams, how with the help of these resistances you can get:
(i) 6 Ω
(ii) `6/1` Ω
(iii) 1.5 Ω
Two exactly similar electric lamps are arranged (i) in parallel, and (ii) in series. If the parallel and series combination of lamps are connected to 220 V supply line one by one, what will be the ratio of electric power consumed by them?
A combination consists of three resistors in series. Four similar sets are connected in parallel. If the resistance of each resistor is 2 ohm, find the resistance of the combination.
Five resistors, each 3 Ω, are connected as shown in Fig. Calculate the resistance
- between the points P and Q.
- between the points X and Y.
You are given four ammeters A, B, C and D having the least counts mentioned below:
(I) Ammeter A with least count 0.25 A
(II) Ammeter B with least count 0.5 A
(III) Ammeter C with least count 0.05 A
(IV) Ammeter D with least count 0.1 A
Which of the ammeters would you prefer for doing an experiment to determine the equivalent resistance of two resistances most accurately, when connected in parallel?
You have three resistors of values 2 Ω, 3 Ω, and 5 Ω. How will you join them so that the total resistance is less than 1 Ω? Draw a diagram and find the total resistance.
Two resistors of resistances 2 Ω and 3 Ω are connected in parallel to a cell to draw current 0.5 A from the cell. Draw a labelled diagram of the arrangement
