12th Class Physics Magnetic Effects of Current / करंट का चुंबकीय प्रभाव Question Bank Case Based (MCQs) - Magnetism and Matter

  • question_answer
    Directions (Q. No. 6 to 10):
    Read the following text and answer the  following questions on the basis of the same:
    If we move into space and study the Earth's invisible magnetic field, it wouldn't really look like a bar magnet at all. Earth's magnetic field gets stretched out into a comet-like shape with a tail of magnetism that stretches millions of miles behind the earth, opposite to the Sun. The Sun has a wind of gas that pushes the earth’s field from the left to the right in the picture.
     
    The core of the Earth is an electromagnet. Although the crust is solid, the core of the Earth is surrounded by a mixture of molten iron and nickle.
    The magnetic field of Earth is caused by currents of electricity that flow in the molten core. These currents are hundreds of miles wide and flow at thousands of miles per hour as the Earth rotates. The powerful magnetic field passes out through the core of the Earth, passes through the crust and enters space. This picture shows the solid inner core region (inner circle) surrounded by a molten outer core (the area between the two circles). The currents flow in the outer core, travel outwards through the rest of the earth's interior.
    If the Earth rotated faster, it would have a stronger magnetic field.
     
    By the time the field has reached the surface of Earth, it has weakened a lot, but it is still strong enough to keep your compass needles pointed towards one of its poles. All magnets have two poles: a North Pole and a South Pole The magnetic poles of earth are not fixed on the surface, but wander quite a bit. The pole in the Northern Hemisphere seems to be moving northwards in geographic latitude by about 10 kilometres per year by an average..
    Earth's magnetic field has a:

    A) shape of the magnetic field of a bar magnet.

    B) shape of the magnetic field of a horseshoe magnet.

    C) shape of a sphere.

    D) None of the above

    Correct Answer: D

    Solution :

    Option [d] is correct. Explanation: Earth's magnetic field gets stretched out into a comet-like shape with a tail of magnetism that stretches millions of miles behind the Earth, opposite from the Sun.


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