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
Show how you would connect two 4 ohm resistors to produce a combined resistance of (a) 2 ohms (b) 8 ohms.
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.
In the following figure calculate:
- the total resistance of the circuit
- the value of R, and
- the current flowing in R.
A current of 2 A is passed through a coil of resistance 75 Ω for 2 minutes.
(a) How much heat energy is produced?
(b) How much charge is passed through the resistance?
State the S.I. unit of electrical resistance and define it.
The least resistance obtained by using 2 Ω, 4 Ω, 1 Ω and 100 Ω is:
A coil in the heater consumes power P on passing current. If it is cut into halves and joined in parallel, it will consume power:
Study the following circuit:
On the basis of this circuit, answer the following questions:
i. Find the value of total resistance between the points A and B.
ii. Find the resistance between the points B and C.
iii. Calculate the current drawn from the battery, when the key is closed
OR
iii. In the above circuit, the 16Ω resistor or the parallel combination of two resistors of 8 Ω, which one of the two will have more potential difference across its two ends? Justify your answer.
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.
