Advertisements
Advertisements
प्रश्न
The following circuit diagram shows three resistors 2 Ω, 4 Ω and R Ω connected to a battery of e.m.f 2V and internal resistance 3 Ω. If the main current of 0.25 A flows through the circuit, find:
- the p.d. across the 4 Ω resistors,
- the p.d. across the internal resistance of the cell,
- the p.d. across the R Ω or 2 Ω resistors, and
- the value of R.
Advertisements
उत्तर
Given: I = 0.25 A; R = 4 Ω; r = 3 Ω
(a) p.d. across the 4 Ω
V = IR
= 0.25 × 4
= 1 Volt
(b) p.d. across r of cell
V = IR
= 0.25 × 3
= 0.75 V
(c) `1/"Req" = 1/"R" + 1/2 = 1/2 + 1/2 = 2/2 = 1`
Req = 1 Ω, I = 0.25 A
V = IR
= 1 × 0.25
= 0.25 V
(d) `1/"Req" = 1/"R" + 1/2`
`1/"Req" = (2 + "R")/"2R"`
Req = `"2R"/(2 + "R")`
Total Resistance = R + r + Req
= `4 + 3 + "2R"/("R + 2")`
`= 7 + "2R"/(2 + "R")`
R = `"V"/"I"`
∴ `7 + "2R"/(2 + "R") = 2/(1/4)`
∴ `"2R"/(2 + "R") = 2 xx 4 - 7`
∴ `"2R"/(2 + "R") = 8 - 7`
∴ 2R = (2 + R)
∴ 2R - R = 2
R = 2 Ω
संबंधित प्रश्न
If the charge on an electron is 1.6 × 10−19 coulombs, how many electrons should pass through a conductor in 1 second to constitute 1 ampere current?
In the circuit diagram given below five resistances of 10 Ω, 40 Ω, 30 Ω, 20 Ω, and 60 Ω are connected as shown to a 12 V battery.
Calculate:
(a) total resistance in the circuit.
(b) total current flowing in the circuit.
Ten bulbs are connected in a series circuit to a power supply line. Ten identical bulbs are connected in a parallel circuit to an identical power supply line.
(a) Which circuit would have the highest voltage across each bulb?
Two resistors of 2.0 Ω and 3.0 Ω are connected (a) in series (b) in parallel, with a battery of 6.0 V and negligible internal resistance. For each case draw a circuit diagram and calculate the current through the battery.
Tick(✓) the correct choice in the following:
The outer casing of an electric iron is generally connected to earth in order
to
Two cells each having an e.m.f. of 2 V and an internal resistance of 2Ω are
connected (a) In series, and ( b) In para 1le l as shown in fig. . What is the
current flowing through the cir cu it in each_ case?
State the condition when it is advantageous to connect cells in series.
Which of the following represents voltage?
Match the following:
| 1. | 1 mA | a. | series |
| 2. | 1 pA | b. | ohmmeter |
| 3. | Ammeter | c. | 10-6 ampere |
| 4. | Electrical resistivity | d. | 10-3 ampere |
