Explanation:
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<span>A wire carrying electric current will produce a magnetic field with closed field lines surrounding the wire.Another version of the right hand rules can be used to determine the magnetic field direction from a current—point the thumb in the direction of the current, and the fingers curl in the direction of the magnetic field loops created by it. See.<span>The Biot-Savart Law can be used to determine the magnetic field strength from a current segment. For the simple case of an infinite straight current-carrying wire it is reduced to the form <span><span>B=<span><span><span>μ0</span>I</span><span>2πr</span></span></span><span>B=<span><span><span>μ0</span>I</span><span>2πr</span></span></span></span>.</span><span>A more fundamental law than the Biot-Savart law is Ampere ‘s Law, which relates magnetic field and current in a general way. It is written in integral form as <span><span>∮B⋅dl=<span>μ0</span><span>Ienc</span></span><span>∮B⋅dl=<span>μ0</span><span>Ienc</span></span></span>, where Ienc is the enclosed current and μ0 is a constant.</span><span>A current-carrying wire feels a force in the presence of an external magnetic field. It is found to be <span><span>F=Bilsinθ</span><span>F=Bilsinθ</span></span>, where ℓ is the length of the wire, i is the current, and θ is the angle between the current direction and the magnetic field.</span></span>Key Terms<span><span>Biot-Savart Law: An equation that describes the magnetic field generated by an electric current. It relates the magnetic field to the magnitude, direction, length, and proximity of the electric current. The law is valid in the magnetostatic approximation, and is consistent with both Ampère’s circuital law and Gauss’s law for magnetism.</span><span>Ampere’s Law: An equation that relates magnetic fields to electric currents that produce them. Using Ampere’s law, one can determine the magnetic field associated with a given current or current associated with a given magnetic field, providing there is no time changing electric field present.</span></span>
The discovery of gallium was significant as it confirmed Mendeleev’s predictions and showed the usefulness of his table.
Answer: Option First
<u>Explanation:
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In 1871, Mendeleev prepared a periodic table of all known elements to study their properties. While making the table, he left some places in the table for elements that were yet to be discovered. One of the elements was eka-aluminium.
In 1875, a French scientist Paul Emile Francois Lecoq de Boisbaudran discovered a new element spectroscopically in the course of examining zinc blende. This newly discovered element showed the same properties as predicted by Mendeleev for the eka-aluminium with an atomic weight 69.
Later, the specific gravity of the element was also found to be the same as predicted by Mendeleev i.e. 5.9. After this, Lepoq named the element as Gallium, which confirmed Mendeleev’s predictions and made his periodic table worthier.