Advertisements
Advertisements
प्रश्न
An electric lamp A of 40 W and another electric lamp B of 100 W are connected to 220 V supply. Calculate the ratio of their filament resistances?
Advertisements
उत्तर
P = `"V.I" = "V.V"/"R"`
`40 = (220)^2/"R"_"A"`
RA = `(220 xx 220)/40`
RA = 110 × 11
P = `"V"^2/"R"`
`100 = (220)^2/"R"_"B"`
`"R"_"B" = (220 xx 220)/100`
RB= 22 × 22
`"R"_"A"/"R"_"B" = (110 xx 11)/(22 xx 22) = 5/2 = 5 : 2`
`"R"_"A"/"R"_"B" = 5: 2`
संबंधित प्रश्न
Why is an electric light bulb not filled with air? Explain why argon or nitrogen is filled in an electric bulb.
1k Wh = ______J
What is the resistance, under normal working conditions of a 240 V electric lamp rated at 60 W? If two such lamps are connected in series across a 240 V mains supply, explain why each one appears less bright.
An electric iron rated 750 W is operated for 2 hours/day. How much energy is consumed by the electric iron for 30 days?
State two advantages of filling an inert gas in an evacuated electric filament lamp.
How does the heat produced by die passage of current in a metallic wire depend on the time of passage of current in the wire?
Three 250 W heaters are connected in parallel to a 100 V supply, Calculate total current taken from the supply.
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.
Using a long extension cord in which each conductor has a resistance of 8Ω, a bulb marked as '100 W, 200 V' is connected to a 220 V dc supply of negligible internal resistance as shown in the figure. The power delivered to the bulb is ______ W.
