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Physical Science
161)Television signal cannot be received ordinarily beyond a particular distance due to
	weakness of the signal		weak antenna
	curvature of the earth		absorption of signals in the air
Answer :
162)What is the use of a radar?
	for receiving signals in a radio receiver		for studying the movement of planets
	detecting the position of aeroplanse		for studying sunspots
Answer :
163)If you stand in a room, where two adjecent walls are covered with plane mirrors then total number of your images will be
	2		infinite
	3		5
Answer :
164)Assertion : The acceleration due to gravity increases with height above the earth's surface Reason : Gravitational force increases with height
	Both Assertion and Reason are correct and Reason explains Assertion		Both Assertion and Reason are correct and Reason does not explain Assertion
	Assertion is correct but Reason is wrong		Both Assertion and Reason are wrong
Answer :
165)Assertion : Objects appear weightless inside an orbiting spacecraft. Reason : Objects in circular motion experience centripetal force
	Both Assertion and Reason are correct and Reason explains Assertion		Both Assertion and Reason are correct and Reason does not explain Assertion
	Assertion is correct but Reason is wrong		Both Assertion and Reason are wrong
Answer :
166)Assertion : The earth revolves around the sun in ellliptical orbit Reason: The sun always attracts the earth with the same force.
	Both Assertion and Reason are correct and Reason explains Assertion		Both Assertion and Reason are correct and Reason does not explain Assertion
	Assertion is correct but Reason is wrong		Both Assertion and Reason are wrong
Answer :
167)Assertion : A steel needle can be made to float on water Reason: When an object is immersed in water it experiences an upthrust.
	Both Assertion and Reason are correct and Reason explains Assertion		Both Assertion and Reason are correct and Reason does not explain Assertion
	Assertion is correct but Reason is wrong		Both Assertion and the Reason are wrong
Answer :
168)Assertion : Apool of water looks ahallower than it actually is Reason : Light bends towards the normal while travelling from water to air.
	Both Assertion and Reason are correct and Reason explains Assertion		Both Assertion and Reason are correct and Reason does not explain Assertion
	Assertion is correct but Reason is wrong		Both Assertion and Reason are wrong
Answer :
169)What type of mirror is used in the head lamps of a car?
	Plane mirror		Spherical concave mirror
	Spherical convex mirror		parabolic concave mirror
Answer :
170)The sun remain visible for some time after it actually sets below the horizon, due to
	scattering of light		atmospheric refraction of light
	dispersion of light		persistence of vision
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171)If there were no atomosphere, the length of the day would
	increase		decrease
	remian unchanged		be half
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172)The twinkling of stars can be partly attributed to
	convection current in the atmosphere		intermittent shining
	atmospheric refraction		unstable motion of the earth
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173)Planets do not twinkle because
	they emit light continuously		they are nearer to us and so their light does not passes through the atmosphere
	they are nearer to us and so minor variations in their intensity are not noticeable		they are luminous sources of light
Answer :
174)Rainbow is formed due to
	refraction		total internal reflection
	dispersion		dispersion and total internal relection
Answer :
175)When white light passes through a glass prism, it dispersed in colours because
	different colours have different speeds in glass		glass imparts colour to the light
	of diffraction of light		of interference of light
Answer :

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