Advertisements
Advertisements
प्रश्न
Define watt. Write down an equation linking watts, volts and amperes.
Advertisements
उत्तर
Watt is the unit of power. One watt can be defined as the power consumed by an electrical device if it is operated at a potential difference of 1 V and it carries a current of 1 A. That is:
1 watt = 1 volt x 1 ampere
APPEARS IN
संबंधित प्रश्न
At what frequency is AC supplied to residential houses?
What is consumed using different electrical appliances, for which electricity bills are paid?
Name the commercial unit of electric energy.
What is the meaning of the symbol kWh? Which quantity does it represent?
Write the formula for electric power in terms of potential difference and current.
When an electric lamp is connected to 12 V battery, it draws a current of 0.5 A. The power of the lamp is:
(a) 0.5 W
(b) 6 W
(c) 12 W
(d) 24 W
Which of the following is the most likely temperature of the filament of an electric light bulb when it is working on the normal 220 V supply line?
(a) 500°C
(b) 1500°C
(c) 2500°C
(d) 4500°C
1Kwh =`( 1 "volt "xx 1 am pere xx.............)/1000`
Two resistors A and B of 4 Ω and 6 Ω respectively are connected in parallel. The combination is connected across a 6 volt battery of negligible resistance. Calculate the power supplied by the battery.
Two resistors A and B of 4 Ω and 6 Ω, respectively are connected in parallel. The combination is connected across a 6 volt battery of negligible resistance. Calculate the power dissipated in each resistor.
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.
Why is the heating element of an electric oven wound on a helix? State the reason.
An electric heater is rated 220 V, 550 W. Electrical energy is also measured in kWh. What do you understand by a kilo-watt-hour?
What is the resistance of an appliance rated at V volt, P watt?
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?
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.
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?
1 mV is equal to:
Compare the power used in the 2 Ω resistor in each of the following circuits:
- a 6 V battery in series with 1 Ω and 2 Ω resistors
- a 4 V battery in parallel with 12 Ω and 2 Ω resistors.
