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प्रश्न
What do you mean by power rating of an electrical appliance? How do you use it to calculate
(a) the resistance of the appliance and
(b) the safe limit of the current in it, while in use?
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उत्तर
An electrical appliance such as electric bulb, geyser etc. is rated with power (P) and voltage (V) which is known as its power rating. For example: If an electric bulb is rated as 50W-220V, it means that when the bulb is lighted on a 220 V supply, it consumes 50 W electrical power.
(a) To calculate the resistance of the appliance, the expression is:
Resisteance , R = `"V"^2/"P"`
(b) The safe limit of current I is : I = `"P"/"V"`
संबंधित प्रश्न
Find the expression for the resistors connected in series and write the two characteristics of it. (Draw figure).
Why is the series arrangement not used for domestic circuits?
Write any two characteristics of a series combination of resistors.
Find the equivalent resistance between points A and B
An electrical appliance has a resistance of 25 Ω. When this electrical appliance is connected to a 230 V supply line, the current passing through it will be:
(a) 0.92 A
(b) 2.9 A
(c) 9.2 A
(d) 92 A
Name the material of wire used for making standard resistances. Give a reason.
Define the term resistivity and state its S.I. unit. Which will have higher resistivity a conductor or an insulator.
Two resistors having 2Ω and 3Ω resistance are connected—(i) in series, and (ii) in parallel. Find the equivalent resistance in each case.
What is the maximum resistance which can be made using five resistors each of `1/5` W?
