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प्रश्न
The following table gives the electrical appliances used, their power and the average time for which they are used each day in a home. Estimate the monthly electricity bill if the rate is 60 paise per unit.
| Sr.no. | Name | Nos. | Power rating | Time/day |
| 1 | Bulb | 4 | 100 W | 7.5 hr |
| 2 | Fans | 2 | 50 W | 10 hr |
| 3 | T.V. | 1 | 100 W | 2 hr |
| 4 | Iron | 1 | 500 W | 1 hr |
| 5 | Electric stove | 1 | 750 W | 2 hr |
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उत्तर
We first calculate the total kWh consumption of each appliance per day. This is done is below:
(1) Bulbs: kWh consumption =`(4 xx 100)/1000 "kW" xx 7.5 "h" = 3 "kWh"`
(2) Fans: kWh consumption = `2 xx 50/1000 "kW" xx 10 "h" = 1 "kWh"`
(3) T.V. kWh consumption = `1 xx 100/1000 "kW" xx 2 "h" = 0.2 "kWh"`
(4) Iron: kWh consumption = `1 xx 500/1000 "kW" xx "1 h" = "0.5 kWh"`
(5) Electric stove: kWh consumption = `1 xx 750/1000 "kW" xx "2 h" = "1.5 kWh"`
∴ Total kWh consumption per day = (3 + 1 + 0.2 + 0.5 + 1.5) kWh
= 6.2 kWh = 6.2 unit
∴ No. of.units consumed in one month = 6.2 × 30 unit = 186 units
∴ Monthly electricity bill = 186 × 60 paise = Rs. 111.60.
संबंधित प्रश्न
The SI unit of energy is :
(a) joule
(b) coulomb
(c) watt
(d) ohm-metre
The table below shows the current in three different electrical appliances when connected to the 240 V mains supply:
| Appliance | Current |
| Kettle | 8.5 A |
| Lamp | 0.4 A |
| toaster | 4.8 A |
- Which appliance has the greatest electrical resistance? How does the data show this?
- The lamp is connected to the main supply by using a thin, twin-cored cable consisting of live and natural wires. State two reasons why this cable should not be used for connecting the kettle to the mains supply.
- Calculate the power rating of the kettle when it is operated from the 240 V mains supply.
- A main takes the kettle abroad where the mains supply is 120 V. What is the current is the kettle when it is operated from the 120 V supply?
State and define the household unit of electricity.
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.
State two advantages of filling an inert gas in an evacuated electric filament lamp.
What would happen and why, to an electric bulb when it is connected across a supply of voltage (i) lower (ii) higher than its proper rating?
A. bulb is rated at 100W, 250V and another one at 60W, 250V. What is the current flowing in the circuit if the two bulbs are put in series across a 220 V mains supply?
A cooler of 1500 W, 200 volts and a fan of 500 W, 200 volts are to be used from a household supply. The rating of fuse to be used is:
1 kWh = ____________
