MCQ Conservation of Energy and Power Chapter 10 Class 9 Science Advertisement MCQ’s For All Chapters – Science Class 9th 1. According to the law of conservation of energy, energy can beCreated and destroyedTransformed from one form to anotherLost completely during conversionCreated by machinesQuestion 1 of 202. The total energy before and after a transformation remainsDoubledDecreasedConstantHalfQuestion 2 of 203. During free fall, potential energy of an objectIncreasesDecreasesRemains constantBecomes zero instantlyQuestion 3 of 204. During free fall, the loss in potential energy appears asKinetic energyHeat energyElectrical energyMagnetic energyQuestion 4 of 205. The total mechanical energy (potential + kinetic) of a freely falling body isZeroConstantIncreasingDecreasingQuestion 5 of 206. At the highest point of a free fall, an object hasOnly kinetic energyOnly potential energyBoth energies equalNo energyQuestion 6 of 207. When a freely falling object is just about to touch the ground, it hasOnly potential energyOnly kinetic energyHalf kinetic and half potential energyNo energyQuestion 7 of 208. The total mechanical energy of a freely falling body ignoring air resistance isDecreasingConstantIncreasingZeroQuestion 8 of 209. The expression for total mechanical energy of a body ismgh + ½mv²½mv² + F×smgh – ½mv²F×s – mghQuestion 9 of 2010. The term “rate of doing work” refers toForcePowerEnergyVelocityQuestion 10 of 2011. The formula for power isWork × TimeForce × DisplacementWork ÷ TimeEnergy × TimeQuestion 11 of 2012. The SI unit of power isJouleWattNewtonPascalQuestion 12 of 2013. One watt is equal to1 joule per second1 newton per metre1 joule per hour1 newton per secondQuestion 13 of 2014. If a machine does 100 J of work in 2 seconds, its power is50 W100 W200 W25 WQuestion 14 of 2015. Power of 1 kilowatt is equal to100 J/s1000 J/s10 J/s10,000 J/sQuestion 15 of 2016. If two girls climb the same height but one does it faster, thenBoth have equal powerBoth have equal energy but different powerThe slower one has more powerThe faster one does less workQuestion 16 of 2017. Power measuresThe rate of energy transferTotal energy usedThe energy of motionThe total work doneQuestion 17 of 2018. A girl lifts a weight of 400 N to a height of 8 m in 20 s.Her power is160 W320 W80 W400 WQuestion 18 of 2019. A boy of weight 500 N climbs a 6.75 m staircase in 9 s.His power is300 W375 W350 W400 WQuestion 19 of 2020. Average power is defined asTotal time ÷ total workTotal work ÷ total timeWork × TimeForce ÷ DistanceQuestion 20 of 20 Loading...
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