Advertisements
Advertisements
प्रश्न
An electric iron is rated 220 V, 2 kW. If the iron is used for 3h daily find the cost of running it for one week if it costs ₹ 4.25 per kWh.
उत्तर
Given,
Power (P) = 2 kW,
Voltage (V) = 220V
Time (t) = 7 x 3 = 21 h
From relation,
E = P x t
Substituting the values in the formula above, we get,
E = 2 x 21 = 42 per kWh
Cost for 1 kWh of energy = ₹ 4.25
Total cost for 42kWh of energy = 4.25 x 42 = ₹ 178.50
संबंधित प्रश्न
An electric iron of resistance 20 Ω takes a current of 5 A. Calculate the heat developed in 30 s.
Two exactly similar heating resistances are connected (i) in series, and (ii) in parallel, in two different circuits, one by one. If the same current is passed through both the combinations, is more heat obtained per minute when they are connected in series or when they are connected in parallel? Give reason for your answer.
Identify the figure and give its use.
Write two devices based on the heating effect of electric current.
Heating effect of current is called ______
The heating element of an electric iron is made up of:
How does use of a fuse wire protect electrical appliances?
(a) Observe the diagram given below and state whether the bulb will glow or not when we switch on K.
(b) Is it safe to handle the bulb when the switch is OFF?
(c) Give a reason for your answer in (b).
Two students decided to investigate the effect of water and air on iron object under identical experimental conditions. They measured the mass of each object before placing it partially immersed in 10 ml of water. After a few days, the object were removed, dried and their masses were measured. The table shows their results.
| Student | Object | Mass of Object before Rusting in g |
Mass of the coated object in g |
| A | Nail | 3.0 | 3.15 |
| B | Thin plate | 6.0 | 6.33 |
What might be the reason for the varied observations of the two students?
In which of the following applications of Iron, rusting will occur most? Support your answer with valid reason.
| A | B | C | D |
 |
 |
 |
 |
