| 1. | A rectangular coil of copper wire is rotated in a magnetic field) The direction of induced current changes once in each ? | |
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One-fourth revolution
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Half revolution
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One revolution
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Two revolutions
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Report Question| 2. | choose the statement which is/ are incorrect ? | |
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The core of an electromagnet must be soft iron because soft iron losses all of its magnetism when current in the coil is switched off.
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If steel is used for making the core of an electromagnet, the steel does not lost all its magnetism when the current is stopped and it becomes a permanent magnet.
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An electromagnet is a magnet consisting of a long coil of insulated copper wire wrapped around a soft iron core that is magnetized only when electric current is passed through the coil.
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None of the above.
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| 3. | On increasing number of turns magnetic field of a solenoid ? | |
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Increase
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no effects
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Decrease
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none of these
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| 4. | The most suitable material for making the core of an electromagnet is ? | |
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Steel
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Aluminium
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Brass
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Soft iron
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| 5. | A 3-Pin mains plug is fitted to the cable for a 1 kw electric kettle to be used on a 250 v a.c. supply. which of the following statements is not correct ? | |
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A 13 A fuse is the most appropriate value to use
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The green wire should be connected to the earth pin.
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The fuse should be fitted in the live wire
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The neutral wire is coloured black
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| 6. | Which of the following statement is or are correct ? | |
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The direction of magnetic field at a point is the direction of the resultant force acting on a hypothetical north pole place at that point
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The magnetic field lines always begin from the N-pole of a magnet and end on the S-pole of the magnet.
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The space surrounding a magnet in which magnetic force is exerted is called a magnetic field
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All the above
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| 7. | The most important safety method used for protecting home appliances from short-circuiting or Overloading is ? | |
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use of electric meter
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use of fuse
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use of stabilizers
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earthing
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| 8. | Earth wire carries ? | |
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heat
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voltage
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current
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no current
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| 9. | Which of the following statement is not correct about the magnetic field ? | |
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Outside the magnet, magnetic field lines go from South to North pole of the magnet.
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Direction of tangent at any point on the magnetic field line curve gives the direction of magnetic field at that point.
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Magnetic field line do not interest each other.
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Magnetic field lines form a continuous closed curve.
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| 10. | Overloading is due to ? | |
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accidental hike in supply voltage
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fault in the appliances
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Insulation of wire is damaged
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All of the above
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