Advertisements
Advertisements
प्रश्न
A. bulb is rated at 100W, 250V and another one at 60W, 250V. What is the current flowing in the circuit if the two bulbs are put in series across a 220 V mains supply?
Advertisements
उत्तर
The resistance of first bulb = `"V"^2/"P"_1 = (250 xx 250)/100` Ω = 625 Ω
Resistance of second bulb = `"V"^2/"P" = (250 xx250)/60` Ω = `3125/3` Ω
∴ Resistance of the circuit containing the two bulbs in series
`= (625 + 3125/3) Omega = 5000/3 Omega`
∴ Current flowing `= 200 div (5000/3)`A
`=(220 xx 3)/5000` A `= (220 xx 3)/5000 xx 1000 "mA" = 132 "mA"`
संबंधित प्रश्न
What is the SI unit of electric energy?
A current of 2 A is passed through a coil of resistance 75Ω for 2 minutes. (a) How much heat energy is produced? (b) How much charge is passed through the resistance?
A bulb marked 12 V, 24 W operated on a 12 volt battery for 20 minutes. Calculate:
(i) the current flowing through it, and
(ii) the energy consumed
A battery of e.m.f 15 V and internal resistance 2 Ω is connected to two resistors of resistance 4 ohm and 6 ohm joined in series. Find the electrical energy spent per minute in 6 ohm resistor.
A coil of copper wire is connected to a galvanometer. What would happen if a bar magnet is:
(i) Pushed into the coil with its north pole entering first?
(ii) Held at rest inside the coil?
(iii) Pulled out again?
Household wiring for lamp connections can either be done in parallel or in series.Which one would you prefer? Give a reason for your answer.
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 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.
A house is provided with 15 bulbs of 40W, 5 bulbs of 100W, 5 fans of 80 W, and one heater of 1.0 kW. Each day bulbs are used for 4h, fans for lOh, and heater for 2h. The voltage of mains is 220 V. Calculate:
(i) Maximum power of the circuit in the house,
(ii) maximum current capacity of the main fuse in the house,
(iii) the electrical energy consumed in a week,
(iv) cost of electricity consumed at 1.25 Rs. per kWh.
The unit of e.m.f. of a cell is ____________.
