The energy consumed by electrical appliances is given by the equation
H = Pt, where P is the power of the appliance and t is the time
Using this formula, the energy consumed by a TV of power ration 250 W, can be calculated as follows:
H = 250 W × 3600 seconds = 9 × 105 J
Similarly, the energy consumed by a toaster of power rating 1200 W is
H = 1200 W × 600 s = 7.2 × 105 J
From the calculations, it can be said that the energy consumed by the TV is greater than the toaster.
Answered by Shivani Kumari | 2 years agoExplain the following.
a. Why is the tungsten used almost exclusively for filament of electric lamps?
b. Why are the conductors of electric heating devices, such as bread-toasters and electric irons, made of an alloy rather than a pure metal?
c. Why is the series arrangement not used for domestic circuits?
d. How does the resistance of a wire vary with its area of cross-section?
e. Why copper and aluminum wires are usually employed for electricity transmission?
An electric heater of resistance 8 Ω draws 15 A from the service mains 2 hours. Calculate the rate at which heat is developed in the heater.
Two lamps, one rated 100 W at 220 V, and the other 60 W at 220 V, are connected in parallel to the electric mains supply. What current is drawn from the line if the supply voltage is 220 V?
Compare the power used in the 2 Ω resistor in each of the following circuits:
(i) a 6 V battery in series with 1 Ω and 2 Ω resistors, and
(ii) a 4 V battery in parallel with 12 Ω and 2 Ω resistors.
A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 Ω resistance, which may be used separately, in series, or in parallel. What are the currents in the three cases?