Physics MCQs

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Gravitational mass is the Ratio of weight of a body and acceleration due to gravity. Gravitational mass is the mass of a body as measured by its gravitational attraction for other bodies.

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Microwave Oven strictly works on the principle of dipole movement of water molecule. A microwave oven is an electric oven that heats and cooks food by exposing it to electromagnetic radiation in the microwave frequency range.

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Gamma rays is commonly used in gemstone industry to change white topaz into blue topaz. Because white topaz is heat-treated to turn into blue topaz, the value of blue topaz is often decreased.

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The joule is the unit of energy in the International System of Units. It is equal to the work done on an object when a force of one Newton acts on that object in the direction of the force’s motion through a distance of one meter. One joule of work is said to be done when a force of 1 N causes a displacement of 1 m.

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Alpha radiation is not used in radiotherapy because it cannot penetrate human skin. Alpha particles are a highly ionizing form of particle radiation with a short range. They can be stopped by a few centimeters of air or by skin. This means that external therapy would be useless because the alpha radiation would not be able to enter the body.  Alpha particles have a very large atomic volume. They are given additional mass by the two neutrons they contain. This facilitates ionization by coulombic interaction or direct collision of the alpha particle with atomic electrons.  Radiation therapy is a treatment that uses ionizing radiation to kill or control the growth of malignant cells. It is often delivered by a linear particle accelerator.

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Albert Einstein was the founder of Theory of Relativity. According to Einstein’s theory, mass m is equivalent to energy E given by the relation E = mc^2 where c is speed of light in vacuum. Albert Einstein was awarded the 1921 Nobel Prize in Physics for his contribution to the field of Theoretical Physics.

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Nuclear Reactors uses Controlled Nuclear Fission to generate electricity. A nuclear reactor splits the atoms of nuclear fuel (eg. uranium) to generate energy to turn water into steam to drive turbine generators. Nuclear fission is the splitting of a heavy nucleus into two lighter ones. Fission was discovered in 1938 by the German scientists Otto Hahn, Lise Meitner, and Fritz Strassmann.

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The Time of Flight, Horizontal Range and the Maximum Height of an object are independent of mass of the object during the projectile motion.

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Centripetal force is the force required to move a body uniformly in a circle. This force acts along the radius and towards the centre of the circle. Centrifugal force is the force that arises when a body is moving actually along a circular path by virtue of the tendency of the body to regain its path.

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The work done by a variable force is given by the area under the force curve and the displacement axis. W = Area ABCDA