| 1. | Consider The Following Statements And Choose The Incorrect One ? | |
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The resistance of a wire is inversely proportional to the square of its diameter.
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Short length of a thick wire is used for getting low resistance; and long length of a thin wire is used for getting high resistance.
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A thick wire has more resistance; and a thin wire has less resistance.
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The resistance of all pure metals increases on raising the temperature; and decreasing on lowering the temperature.
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Report Question| 2. | One coulomb charge is equivalent to the charge contained in ? | |
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2.65 × 10 to the power 18 electrons
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6.25 × 10 to the power 18 electrons
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6.2 × 10 to the power 19 electrons
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2.6 × 10 to the power 19 electrons
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| 3. | Three equal resistances when combined in series are equivalent to 90w. Their equivalent resistance when combined in parallel will be ? | |
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810 W
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30 W
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270 W
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10 W
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| 4. | For which of the following substances, resistance decreases with temperature ? | |
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Copper
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Platinum
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Carbon
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Mercury
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| 5. | A cylindrical conductor of length l and uniform area of cross section A has resistance R. Another conductor of length 2l and resistance R of the same material has area of cross- section ? | |
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2A
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3A
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3A /2
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A /2
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| 6. | 100 J of heat is produced each second in a 4ohm resistor. The potential difference across the resistor will be ? | |
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25 V
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20 V
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10 V
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30 V
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| 7. | Two devices are connected between two points say A and B in parallel. The physical quantity that will remain the same between the two points is ? | |
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voltage
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resistance
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current
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None of these
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| 8. | Read The Following Sentences Carefully, And Choose The Incorrect One ? | |
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Nichrome alloy is used for making the heating elements of electrical appliances.
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The heating elements of electrical heating appliances such as electric iron and toaster are made of an alloy rather than a pure metal.
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Alloy of nickel, chromium, manganese and iron having a resistivity of about 60 times more than that of copper.
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Nichrome undergoes oxidation very easily at a high temperature.
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| 9. | The resistance of a wire of length 300 m and cross-section area 1.0 msq made of material of resistivity 1.0 × 10?7 ohm-m is: ? | |
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20 ohm
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30 ohm
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3 ohm
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2 ohm
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| 10. | When a 4 V battery is connected across an unknown resistor there is a current of 100 mA in the circuit. The value of the resistance of the resister is ? | |
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0.4 ohm
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4 ohm
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40 ohm
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400 ohm
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