Advertisements
Advertisements
प्रश्न
Why are the conductors of electric heating devices, such as bread-toasters and electric irons, made of an alloy rather than a pure metal?
Advertisements
उत्तर
The conductors of electric heating devices, such as bread toasters and electric irons, are made of alloy instead of pure metal for the following reasons:
- The resistivity of an alloy is higher than that of a metal, which produces a large amount of heat.
- Oxidation of alloys does not occur quickly at high temperatures.
- There is a negligible change in their resistance with an increase in temperature.
संबंधित प्रश्न
Name any two effects of electric current.
The elements of electrical heating devices are usually made of:
(a) tungsten
(b) bronze
(c) nichrome
(d) argon
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.
Statement 1 : Electric current ( flow of electrons ) creates heat in the resistor.
Statement 2 : Heat in the resistor is created according to the rule of energy conservation.
Explain Statement 1 with the help of Statement 2.
Give scientific reason :
In the electric equipment producing heat e.g. iron, electric heater, boiler, toaster, etc., an alloy such as Nichrome is used, not pure metals.
Name the factors on which the heat produced in a wire depends when current is passed in it, and state how does it depend on the factors stated by you.
Name any six domestic appliances based on the heating effect of electric current.
The electricity bill specifies the usage in _______.
What is the heating effect of electric current?
Write scientific reason.
A coil made up of alloy Nichrome is used in the electric heater cooker as a resistor.
Name some devices that run using heat effect of electric current
The heating element of an electric iron is made up of:
Three incandescent bulbs of 100 W each are connected in series in an electric circuit. In another circuit another set of three bulbs of the same wattage are connected in parallel to the same source.
- Will the bulb in the two circuits glow with the same brightness? Justify your answer.
- Now let one bulb in both the circuits get fused. Will the rest of the bulbs continue to glow in each circuit? Give reason.
An electric cell produces electricity from the ______ ______ in it.
Explain why fuse wire is always connected in a series arrangement.
In which of the following applications of Iron, rusting will occur most? Support your answer with valid reason.
| A | B | C | D |
 |
 |
 |
 |
An electric kettle consumes 1 kW of electric power when operated at 220 V. A fuse wire of what rating must be used for it?
What is the heating effect of electric current?
