Advertisements
Advertisements
Question
Solution
Electrical energy is defined as the total amount of work done to maintain current in a circuit in a given time. Its SI unit is joule.
The rate at which electrical energy is consumed per unit time is called electrical power. It is denoted by P. i.e., Its SI unit is watt.
Electrical power = `"Electrical energy"/"time"`
The other name of kWh is Board of Trade Unit (BOTU).
APPEARS IN
RELATED QUESTIONS
Electrical power P is given by the expression P = (Q × V) ÷ time. What do the symbols Q and V represent?
Name the S.I. unit of electrical energy. How is it related to Wh?
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.
The diagram below shows a magnetic kept just below the conductor AB which is kept in North South direction.
(i) In which direction will the needle deflect when the key is closed ?
(ii) Why is the deflection produced ?
(iii) What will be the change in the deflection if the magnetic needle is taken just above the conductor AB ?
(iv) Name one device which works on this principle.
You are required to connect a bulb, a fan and a socket outlet to the mains in one set A and an air-conditioner and a refrigerator to the mains in other set B. Will you recommend the wire of same thickness and same insulation in both? explain your answer.
At what voltage is the electric power generated at the generating station? Explain the transmission of this power to your house.
An immersion rod having resistance of 50 Ω is connected to 220V main supply. Assuming that all the energy generated goes to heat the water, calculate the time taken to heat 5 kg water from 30°C to 100°C.
An electric appliance is rated at 1000 W, 250V. Calculate:
(i) The electrical energy consumed by the appliance in 12 hour.
(ii) The cost of energy consumed at Rs. 1.20 per kWh.
How long would this appliance take to use 1 kWh energy when operated at 250 V?
