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?
In a house two 60 W electric bulbs are lighted for 4 hours, and three 100 W bulbs for 5 hours everyday. Calculate the electric consumed in 30 days.
Calculate the cost of operating a heater of 500 W for 20 hours at the rate of Rs 3.90 per unit.
Explain why, filament type electric bulbs are not power efficient.
Name the S.I unit of electrical energy. How is it related to Wh?
The diagram below shows a magnetic kept just below the conductor AB which is kept in North South direction.
(i) In which direction will the needle deflect when the key is closed ?
(ii) Why is the deflection produced ?
(iii) What will be the change in the deflection if the magnetic needle is taken just above the conductor AB ?
(iv) Name one device which works on this principle.
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.
Why is heating coil wound in the form of a helix in electric stove?
Mention three uses of the carbon arc.
Name two common material used for heating elements.
Which material is the calorimeter commonly made of? Give one reason for using this material.
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?
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?
Three 250 W heaters are connected in parallel to a 100 V supply, Calculate the resistance of each heater.
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?
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 joule.
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.
Unit of electric power may also be expressed as:
