Advertisements
Advertisements
प्रश्न
A battery of e.m.f. 12V and internal resistance 1.6 Ω is connected to two resistors of 4Ω and 6Ω connected in parallel. Calculate:
(i) the current drawn from the battery,
(ii) the power dissipated in each resistor,
(ii)the total power supplied by the battery.
Advertisements
उत्तर
Given: E = 12V, r = 1.6 Ω, R1 = 4 Ω, R2 = 6 Ω
Equivalent resistance in parallel R = `("R"_1"R"_2)/("R"_1 + "R"_2) = (4 xx 6)/(4 + 6) = 2.4 Omega`
Total resistance of circuit = R = r = 2.4 + 1.6 = 4.0 Ω
(i) The current drawn from the battery
I = `"E"/("R" + "r") = 12/4.0 = 3.0` A
(ii) The voltage drop in internal resistance v = Ir = 3.0 × 1.6 = 4.8 V
Voltage across each resistor (connected in parallel) V = E - v = 12 - 4.8 = 7.2 V
Power dissipated in R1 = 4 Ω, P1 = `"V"^2/"R"_1 = (7.2)^2/4 = 12.96` W
Power dissipated in R2 = 6 Ω, P2 = `"V"^2/"R"_2 = (7.2)^2/6 = 8.64` W
(iii) Total power supplied by the battery P = El = 12 × 3 = 36 W.
संबंधित प्रश्न
Which particles are responsible for current in conductors?
Write the formula for electric power in terms of potential difference and current.
The SI unit of energy is :
(a) joule
(b) coulomb
(c) watt
(d) ohm-metre
A current of 0.2 A flows through a wire whose ends are at a potential difference of 15 V.
calculate:
(i) the resistance of the wire and
(ii) the heat energy produced in 1 minute.
An electric toaster draws 8 A current in a 220 V circuit. It is used for 2 h. Find the cost of
operating the toaster if the cost of electrical energy is Rs. 4.50 per kWh.
In an electric radiator or room heater, state with reason, why the porcelain tube wound with a nichrome wire is placed between the pole and principal focus of the parabolic concave reflector.
How does the heat produced by die passage of current in a metallic wire depend on the current in the wire?
An electric heater is rated 220 V, 550 W. What does this statement mean?
Find the energy released by a current of 0.25 amperes flowing through a heater for 5 minutes. The p.d. is 230 V.
A family uses 8 kW of power. Direct solar energy is incident on the horizontal surface at an average rate of 200 W per square meter. If 20% of this energy can be converted to useful electrical energy, how large an area is needed to supply 8 kW?
