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Why is liquid ammonia used in ice plants?

Liquid ammonia acts as a refrigerant in ice plants. Evaporation of a liquid needs heat energy. When liquid ammonia vapourizes, it absorbs large quantities of heat without changing its temperature. For these reasons, ammonia is widely used as a refrigerant. About 17 g of liquid ammonia absorbs 5,700 calories of heat from the surrounding water. This cools the water and …

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Why is it harder to walk uphill than downhill?

It is harder to walk uphill than downhill because you must lift the weight of your body and to do this requires greater energy than that needed for walking on the level. To create this greater energy your muscles require to give extra lift, your heart has more work to do to feed the blood cells and remove their waste …

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Why is it cooler at higher altitudes?

High altitudes normally begin at 1500 metres above sea level. At such altitudes, the atmospheric pressure is considerably lower than at sea level. To give some examples: the pressure at sea level is 14.7 pounds per square inch and it decreases through 4.3 psi at 30,000 ft to 1.6 psi at 50,000 ft. Because of this, the air expands as …

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Why is glass transparent?

These interactions depend on the nature of the light and the nature of the material. For instance, light falling on a leaf encounters many pigment molecules, predominantly chlorophyll. These molecules absorb light from the red and blue ends of the visible spectrum. The remaining light is scattered back because molecules in a leaf are tightly packed and so, we see …

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Why is Einstein famous?

Albert Einstein is famous for his Theories of Relativity which say that nothing in the universe is absolutely still and that all motion is connected all or comparable. Einstein worked out a method of measuring the speed of moving objects, using the three dimension of space-length, height and thickness-and adding the fourth dimension of time. The three space dimensions tell …

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Why is earthing necessary for electrical appliances?

As it’s a safety factor, earthing is essential and mandatory. It’s an electrical connection between the exposed metallic parts of an electrical appliance or installation and the earth, regarded to have zero potential. Proper earthing provides an alternative and easy path for leakage or faulty current to flow. It ensures that any exposed conductive part of the appliance does not …

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