Physics Assertion Reason Questions Part 2
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- Carts with rubber tyre are easier to ply than Iron as force of friction between rubber & road is less than between Iron & road.
- Mercury doesn՚t feel wet as (Force of adhesion) < (F of cohesion)
- Satellite does not need fuel to circle round the earth-as gravitational force between satellite & earth provides centripetal force to move in circular orbit.
- Current is not passed through potentiometer wire for a long time as it gets heated & resistance changes & potential gradient will change.
- In a revolving artificial satellite everything is in a weight less condition. The things in the vessel is also weightless for this reason pressure at a point inside the liquid is nil.
- When the Centre of gravity occupies the highest position, body become a heavy & there is a risk of toppling over passenger, therefore passengers are not allowed to stand on the upper deck of a double decker bus.
- Velocity of light waves in vacuum is a constant quantity & velocity of matter waves in vacuum depends on wavelength
- Wavelength of fast neutrons is very small as compared to the interatomic space & hence not used in the diffraction principle. Wavelength of thermal neutron is of order of interatomic spacing. So it is used in diffraction experiments.
- Metals are coated with alkali so as to have low work function & the electricity can be easily emitted from it.
- For analysis of spectral energy of radiation prism is used as it does not absorb thermal radiations.
- Propagation of an actual wave through a medium the amplitude gradually diminishes due to the resisting effect of the viscous medium & loss in energy.
- With decrement in velocity, increment of sound is more than in dry air.
- Sound exhibits total internal reflection when sound in a medium they have less velocity meet at the surface of another medium with larger velocity at an angle more than critical angle.
- Sound in a building/auditorium does not die immediately after it has ceased to produce it. It continues for some time due to multiple reflections called reverberation.
- Chromatic aberration is produced in lenses because refractive under & consequently focal length is different for different colours of light.
- Achromatic lens combination is cemented with Canada balsam as it is transparent & has refractive index almost equal to the refractive index of glass.
- Current is measured in galvanometer due to torque produced by magnetic field.
- Spherical aberration is due to different in focal length of different parts of lens.
- Coma arises due to different zones of lens produce different lateral magnification. It very close to axis will suffer spherical aberration & coma only.
- When a stop is used with a lens, image is not same a object because different part of objects suffer different magnification.
- Contact lens is held to the cornea by the surface tension of the eye fluid.
- Camera-Large aperture gives blurred image due to aberration.
- Camera-small aperture due to diffraction.
- The layer of oil on water & soap bubbles shows varied colours in white light due to interference of waves reflected from two surfaces of film.
- Brilliant colors are seen in the inner surface of oyster shell & peacock feather due to interference of light.
- As temperature of electrolyte increment, the interval resistant decrement as viscosity of electrolyte is decreased
- Potentiometer is more sensitive than voltmeter because it is based on null deflection method.
- Nichrome is used in electric heater filament because of high sp. Resistance, high Melting point & low temp coefficient Of resistance.
- Current in the conductor flows only when electronic field is established in conductor applies a force in each free electron.
- Syrups & engine oil, which power slowly than water are more viscous.
- Spinning ball are being dragged round by ball, thereby increment air flow on one side & decrement on the another side & a pressure difference is created.
- Bernoulli, yacht, or venture tube theorem aero foil-fluid flows fast an top surface than bottom i.e.. . pressure underneath is increment & above reduced upward force is created which light aircraft.
- Pendulum clock slow in summer because in summer the length increment so temperaure increment & it goes slow.