Advertisements
Advertisements
प्रश्न
An electric motor takes 5 A from a 220 V line. Determine the power of the motor and the energy consumed in 2 h.
उत्तर
Power (P) is given by the expression P = VI
Where,
Voltage,V = 220 V
Current, I = 5 A
P = 220 × 5
P = 1100 W
Energy consumed by the motor = Pt
Where,
Time, t = 2 h
= 2 × 60 × 60
= 7200 s
∴ P = 1100 × 7200
= 7.92 × 106 J
Therefore, power of the motor = 1100 W
Energy consumed by the motor = 7.92 × 106 J
APPEARS IN
संबंधित प्रश्न
What determines the rate at which energy is delivered by a current?
Which uses more energy, a 250 W TV set in 1 hr, or a 1200 W toaster in 10 minutes?
Which particles are responsible for current in conductors?
At what frequency is AC supplied to residential houses?
State the S.I. unit of electrical power.
A current of 0.2 A flows through a wire whose ends are at a potential difference of 15 V.
calculate:
(i) the resistance of the wire and
(ii) the heat energy produced in 1 minute.
A bulb with rating 250 V, 100 W is connected to a power supply of 220 V situated 10 m away using a copper wire of area of cross-section 5 mm2. How much power will be consumed by the connecting wires? Resistivity of copper = 1.7 × 10−8 Ωm
State the S.I. units of electrical power and electrical energy.
(i) Define the household unit of electricity.
(ii) What is the voltage of the electricity that is generally supplied to a house?
Why is the heating element of an electric oven wound on a helix? State the reason.
‘The current rating of a fuse is 5A’. Comment on this statement.
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?
An electric bulb is rated as 100W – 250V. What information does it convey? Calculate the resistance of its filament while glowing.
An electric bulb is rated as 100W – 250V. What information does it convey? Calculate the current through the filament of the bulb.
1 kWh = ____________
What is the commercial unit of electrical energy? Represent it in terms of joules.
A room has AC run for 5 hours a day at a voltage of 220V. The wiring of the room consists of Cu of 1 mm radius and a length of 10 m. Power consumption per day is 10 commercial units. What fraction of it goes in the joule heating in wires? What would happen if the wiring is made of aluminium of the same dimensions?
`[ρ_(Cu) = 1.7 xx 10_(Ωm)^-8, ρ_(Al) = 2.7 xx 10^-8 Ωm]`
