An electric iron rated 750 W is operated for 2 hours/day. How much energy is consumed by the electric iron for 30 days?
An electric bulb is rated at 220 V, 100 W. What is its resistance?
Which uses more energy : a 250 W TV set in 1 hour or a 1200 W toaster in 10 minutes?
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.
How much energy does a 100 W electric bulb transfer in 1 minute?
(a) 100 J
(b) 600 J
(c) 3600 J
(d) 6000 J
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.
1Kwh =`( 1 "volt "xx 1 am pere xx.............)/1000`
When a current I flows through a resistance R for time t, the electrical energy spent is given by:
(a) IRt (b) I²Rt (c) `IR^2t` (d) `I^2R ⁄t`
Two resistors A and B of resistance 4 Ω and 6 Ω respectively are connected in parallel. The combination is connected across a 6 volt battery of negligible resistance. Calculate: (i) the power supplied by the battery, (ii) the power dissipated in each resistor.
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.
What does the unit kilowatt hour measure? Define it.
Why is a concave reflector placed behind the heating element in a room heater.
How does earthing prevent electrical shock?
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.
At what voltage is the electric power generated at the generating station? Explain the transmission of this power to your house.
State (i) the S. I. unit, (ii) the household unit, of electrical energy. How are these units related?
How can electric energy consumed by an electric appliance be calculated in kilowatt hour (kWh)?
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:
An overhead tank of capacity 10 k litre is kept at the top of building 15 m high. Water falls in tank with speed 5`sqrt2` m/s. Water level is at a depth 5 m below ground. The tank is to be filled in `1/2` hr. If efficiency of pump is 67.5% electric power used is ______ W.
