Please select a subject first
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Which of the following characteristic is not suitable for a fuse wire?
(a) thin and short
(b) thick and short
(c) low melting point
(d) higher resistance than rest of wiring
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If the current flowing through a fixed resistor is halved, the heat produced in it will become:
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The electrical resistivities of four materials P, Q, R and S are given below:
| P | `6.84xx10^8`Ωm |
| Q | `1.70xx10^8`Ωm |
| R | ` 1.0xx10^15`Ωm |
| s | `11.0xx10^-7`Ωm |
Which material will you use for making: (a) heating element of electric iron (b) connecting wires of electric iron (c) covering of connecting wires? Give reason for your choice in each case.
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How does the wire in the filament of a light bulb behave differently to the other wires in the circuit when the current flows?
What property of the filament wire accounts for this difference?
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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.
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An electric iron is connected to the mains power supply of 220 V. When the electric iron is adjusted at ‘minimum heating' it consumes a power of 360 W but at 'maximum heating’ it takes a power of 840 W. Calculate the current and resistance in each case.
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Which electric heating device in your home do you think have resistors which control the flow of electricity?
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Write the mathematical expression for Joule’s law of heating.
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Compute the heat generated while transferring 96000 coulombs of charge in two hours through a potential difference of 40 V.
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Write two devices based on the heating effect of electric current.
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The part where the exchange of gases occurs during respiration is:
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The respiratory pigment in human beings is:
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A large quantity of one of the following is removed from our body by lungs:
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In respiration, air passes through:
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A biochemical compound that readily combines with oxygen and distributes it throughout the human body is ____________.
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Assertion: Human being has a complex respiratory system.
Reason: Human skin is impermeable to gases.
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Carefully study the diagram of the human respiratory system with labels A, B, C and D. Select the option which gives correct identification and main function and /or characteristic.
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An electric iron draws a current of 4 A when connected to 220 V mains. Its resistance must be:
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A fuse wire repeatedly gets burnt when used with a good heater. It is advised to use a fuse wire of:
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A current of 1 A is drawn by a filament of an electric bulb. Number of electrons passing through a cross-section of the filament in 16 seconds would be roughly:
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