मराठी

How Many Joules Are There in One Kilowatt-hour? - Science

Advertisements
Advertisements

प्रश्न

 How many joules are there in one kilowatt-hour?

Advertisements

उत्तर

  1 kilowatt-hour = 36,00,000 joules

shaalaa.com
  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 1: Electricity - Exercise 7

APPEARS IN

व्हिडिओ ट्यूटोरियलVIEW ALL [1]

संबंधित प्रश्‍न

What is the SI unit of (i) electric energy, and (ii) electric power?


An electric kettle connected to the 230 V mains supply draws a current of 10 A. Calculate:

(a) the power of the kettle.
(b) the energy transferred in 1 minute.


The diagram below shows a circuit containing a lamp L, a voltmeter and an ammeter,. The voltmeter reading 3 V and the ammeter reading is 0.5 A. 

  

 What is the resistance of the lamp?
 What is the power of the lamp?


Which of the following is likely to be the correct wattage for an electric iron used in our homes? 

(a) 60 W
(b) 250 W
(c) 850 W
(d) 2000 W


An electric bulb is rated at 220 V, 100 W. (a) what is its resistance? (b) what safe current can be passed through it?


An electrical appliance having a resistance of 200Ω is operated at 200 V. Calculate the energy consumed by the appliance in 5 minutes (i) in joules (ii) in kWh.


An electric kettle is rated 2.5 kW, 250 V. Find the cost of running the kettle for two hours at Rs. 5.40 per unit.


A geyser is rated 1500 W, 250 V. This geyer is connected to 250 V mains. Calculate:
(i) the current drawn
(ii) the energy consumed in 50 hours, and
(iii) the cost of energy consumed at Rs. 4.20 per kWh


The diagram shows a coil connected to a center zero galvanometerG . The galvanometer shows a deflect ion to the right when the north pole N of a powerful magnet is moved to the right as shown .

(i) Explain, why the defelct ion occurs in the galvanometer.
(ii ) State whether th e current in the coil is cl ockwise or anticl ockwise
when viewed from the end P.
(iii ) State th e observation in G when the coil is moved away from north
pole N of the magnet keeping the magnet stationary.
(iv)State the observation in G when both the coil and the magnet are
moved to right at th e same speed .


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.


Name three main characteristics of an heating element.


An electric filament lamp is connected to a supply of voltage higher than the recommended value. Give reasons, why compared with a normal performance, the lamp emits a brighter light and its life is shortened.


How does the heat produced by die passage of current in a metallic wire depend on the time of passage of current in the wire?


Three 250 W heaters are connected in parallel to a 100 V supply, Calculate the resistance of each heater.


State other bigger units of electric power and express them in watt.


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.


The resistance of filament of an electric heater is 500 Ω It is operated at 200V for 1 hour daily. Calculate the current drawn by the heater and the energy consumed in kWh, by the heater in a month of 30 days.


A torch bulb is rated at 3 V and 600 mA. Calculate it’s

  1. power
  2. resistance
  3. energy consumed if it is used for 4 hours.

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]`


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×