Physics MCQs

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Bats use SONAR (Sound Navigation & Ranging).Sonar is a technique that uses sound propagation to navigate, communicate with or detect objects on or under the surface of the water, such as other vessels.

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Latent heat is energy released or absorbed, by a body or a thermodynamic system, during a constant-temperature process. So steam at 100 degree centigrade causes more severe burns.

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Surface tension is the tendency of liquid surfaces to shrink into the minimum surface area possible. Surface tension allows insects, usually denser than water, to float and slide on a water surface. It is the reason for the water droplet’s round shape.

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Capillary action is the ability of a liquid to flow in narrow spaces without the assistance of, or even in opposition to, external forces like gravity. The capillary action is among the following works while we wipe with a towel.

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A Svedberg unit (S/ Sv) is utilized to denote sedimentation coefficients, providing specific measurement of a particle based on its sedimentation rate under acceleration. Essentially, it computes how quickly a particle settles to the bottom of a solution. In terms of the time dimension, a Svedberg unit amounts to exactly 10−13 seconds, indicating that it is essentially a measure of time.

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Pure silicon has a negative coefficient of thermal expansion for temperatures and hence it shows contraction effect.

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The SI unit of Linear Momentum is kg m/s Linear Momentum = Mass(kg) x Velocity (m/s) Linear Momentum is the quantity of motion of a moving body. Dimensional Formula of Linear Momentum is [M¹ L¹ T^-1]

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nautical mile is a unit of length. 1 nautical mile is equal to 1.852 x 1000 m Other important units of length are:

• 1 mile = 1.609 x 1000 m
• 1 light year = 9.46 x 10¹⁵ m
• 1 AU = 1.5 x 10¹¹m
• 1 Par sec = 3.1 x 10¹⁶m

Notes:
When an object moves with constant negative acceleration, having positive initial velocity, the velocity-time graph is a straight line having slope more than 90°. When an object moves with constant positive acceleration, having positive initial velocity, the velocity-time graph is a straight line having slope less than 90°.

Notes:
The slope of a straight line joining two points on a velocity-time graph gives the average acceleration between these two points. Depending on the sign of slope, the average acceleration can be positive or negative.