Advertisements
Advertisements
प्रश्न
Water in an electric kettle connected to a 220 V supply took 5 minutes to reach its boiling point. How long will it take if the supply voltage falls to 200 V?
Advertisements
उत्तर
P = `"V"^2/"R"`
Heat gained = `("V"^2)/"R" xx "t"`
`("V"_1^2/"R") xx "t"_1 = ("V"_2^2/"R") xx "t"_2`
t2 = `("V"_1/"V"_2)^2 xx "t"_1`
`= (220/200)^2 xx 300 = 363 "s"`
= 6.05 min
APPEARS IN
संबंधित प्रश्न
An electric motor takes 5 amperes current form a 220 volt supply line. Calculate the power of the motor and electric energy consumed by it in 2 hours.
Calculate the resistance of an electric bulb which allows a 10 A current when connected to a 220 V power source.
A device is used to transform 12 V a.c. to 200 V a.c. What is the name of this device? Name the principle on which it works.
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 bulb is connected to a battery of e.m.f. 6V and internal resistance 2Ω A steady current of 0.5A flows through the bulb. Calculate the resistance of the bulb.
A 100-watt electric bulb is used for 5 hours daily and four 60 watt bulbs are used for 5 hours daily. Calculate the energy consumed (in kWh) in the month of January.
1 kWh = ____________
What is the meaning of electric power of an electrical device? Write its SI unit.
