Physics MCQs

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Diffraction is the slight bending of light as it passes around the edge of an object. The amount of bending depends on the relative size of the wavelength of light to the size of the opening.

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Pascal’s law states that the pressure applied at one point of the liquid is transmitted equally in all directions. This principle is applied in hydraulic lifts for lifting heavy objects.

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During winter ice is formed only on the top layer of a pond or a lake because the water’s surface is usually slightly cooler than the rest of the body of water due to evaporative cooling. As water cools below 4 C, it also becomes slightly less dense, rising to the surface. Ice is also slightly less dense than the slightly warmer water below, so it floats on the water’s surface. Once ice crystals begin to form, they provide nucleation sites for additional ice to grow along the water’s surface. The islands of ice expand, until they cover the entire surface of the water.

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Microwaves are chosen for satellite communication. Its frequency is high and microwaves can pass through the atmosphere of Earth to reach higher orbit satellites. Radio waves get affected by ionosphere and hence aren’t used.

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Normal body temperature of human is 37° C. But when we convert 37° C into Kelvin it becomes 310 K because 0° C = 0°C + 273 = 273 K.

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The surface of tanker will move in forward direction with increasing velocity (as acceleration in uniform), so depth will be larger at the rear end.

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Nicolas Leonard Sadi Carnot was a French mechanical engineer in the French Army, military scientist and physicist, often described as the “father of thermodynamics.” Like Copernicus, he published only one book, the Reflections on the Motive Power of Fire (Paris, 1824), in which he expressed, at the age of 27 years, the first successful theory of the maximum efficiency of heat engines. In this work, he laid the foundations of an entirely new discipline, thermodynamics. Carnot’s work attracted little attention during his lifetime, but it was later used by Rudolf Clausius and Lord Kelvin to formalize the second law of thermodynamics and define the concept of entropy.

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A flywheel is a rotating mechanical device that is used to store rotational energy. Flywheels have a significant moment of inertia and thus resist changes in rotational speed, enabling the engine to run at a constant, uniform motion. In the Industrial Revolution, James Watt contributed to the development of the flywheel in the steam engine.