Advertisements
Advertisements
Question
What is the resistance of an appliance rated at V volt, P watt?
Advertisements
Solution
Let I be the current drawn by the appliance.
Then Power, P = V × I or I = `"P"/"V"`
Now, Resistance R = `"V"/"I"`
Hence, R = V + `"P"/"V" = "V"^2/"P"`.
APPEARS IN
RELATED QUESTIONS
An electric motor takes 5 A from a 220 V line. Determine the power of the motor and the energy consumed in 2 h.
An electric kettle is rated 2.5 kW, 250 V. Find the cost of running the kettle for two hours at Rs. 5.40 per unit.
Fig . shows the essent ial features of a battery operated bell. The hammer strikes the gong when the swi tch is closed . State and explain the effect of using the following material successively to form the core.
(a) Plastic
(b) Steel
(c) Copper
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.
Why is heating element wound on a long porcelain rod in a room heater.
Why is the heating element of an electric oven wound on a helix? State the reason.
What is the function of the split rings in a d.c. motor?
An Electric bulb is marked 100 W, 230 V. What how long would this lamp take to consume one unit of electricity?
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 total energy supplied by the battery in 10 minutes.
What is the commercial unit of electrical energy? Represent it in terms of joules.
