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What are glaciers and icebergs?

You have probably been told about the huge masses of ice that exist at the north and south poles today. You may also h., have heard that thousands of years ago great tongues of ice stretched southward from the north as far as Britain and northern Europe, and that millions of years before many of countries of the southern hemisphere …

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What are galactic superclusters?

Each galaxy has billions of stars. Such galaxies are not uniformly spaced in the universe but exist in groups and clusters; a group containing up to 40-50 galaxies and clusters containing about thousands of galaxies. These along with isolated galaxies may form larger clusters known as galactic superclusters. These are the largest structures of matter found in the universe. Our …

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What are Fizeau’s fringes?

Fizeau’s fringes occur in interferometry. One of the most common methods used to test the flatness of a polished surface is by analysing the interference patterns formed when the surface is placed against another polished flat transparent surface. When two surfaces are fully in contact, a pattern of concentric dark and light circles is seen and these patterns (or fringes) …

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What are ferns?

A fern is any one of a group of about 12,000 species of plants. Unlike mosses, they have xylem and phloem (making them vascular plants). They have stems, leaves, and roots like other vascular plants. Ferns do not have either seeds or flowers (they reproduce via spores). By far the largest group of ferns are the leptosporangiate ferns, but ferns …

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What are eddy currents?

Eddy currents may be defined as currents induced in a thick conductor when it is placed in a changing electric field. Consider a metallic block placed in a continuously changing magnetic field by keeping the block fixed and changing the magnetic field with the help of an alternating current. Due to the continuous change of magnetic flux linked with the …

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