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
1 calorie = _________ joule.
Electrical power P is given by the expression P = (Q × V) ÷ time. What do the symbols Q and V represent?
Name the physical quality which is measured in
(i) Kw (ii) kWh
An electric bulb is rated ‘100 W, 250 V’. What information does this convey?
What are the two main systems of wiring commonly used in houses? Which of these systems mentioned by you is better and why?
An electric kettle is rated 3kW, 250V. What should be the current capacity of the fuse with it?
A cooler of 1500 W, 200 volts and a fan of 500 W, 200 volts are to be used from a household supply. The rating of fuse to be used is:
A electric bulb is rate 220 V, 60 W. its electric cell resistance is nearly
An overhead tank of capacity 10 k litre is kept at the top of building 15 m high. Water falls in tank with speed 5`sqrt2` m/s. Water level is at a depth 5 m below ground. The tank is to be filled in `1/2` hr. If efficiency of pump is 67.5% electric power used is ______ W.
