Advertisements
Advertisements
प्रश्न
State (i) the S. I. unit, (ii) the household unit, of electrical energy. How are these units related?
उत्तर
(i) The S.I. unit of electrical energy is joule (J)
(ii) The household unit of electrical energy is kilo-watt hour (kWh).
Relationship: 1 kWh = 1 kW × 1h
= 1000W × 3600 s
= 3.6 × 106 J.
APPEARS IN
संबंधित प्रश्न
If a bulb of 60W is connected across a source of 220V, find the current drawn by it.
Explain why, filament type electric bulbs are not power efficient.
Write an expression for the electrical power spent in flow of current through a conductor in terms of
(a) Resistance and potential difference, (b) current and resistance.
An electric bulb is rated ‘100 W, 250 V’. What information does this convey?
Define electric power. An electrical device of resistance R is connected across a source of voltage V and draws a current I. Derive an expression for power in terms of current and resistance.
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.
Find the heat produced in joules when a current of 10 amperes flows through a connecting wire of resistance 2 × 10-2 ohms and heating element of resistance 250 ohms for 2 seconds.
The equation I2R seems to suggest that the rate of heating in a resistor is reduced if resistance decreases, whereas equation P = V2/R suggests just the opposite. How do you reconcile this problem?
Find the cost of operating an electric toaster for two hours if it draws 8 A current on a 110 volt circuit. The cost of electrical energy is Rs. 2.50 per kWh.
