Q. The number of significant figures in the distance of one light year, 9.4605 × 10 m is thirtyfivefourthree Answer: five

Q. Dimensions cannot be used to check dimensional correctness of a formulaconvert unitsfind value of the constant of proportionality in an equationdeduce a relation among physical quantities Answer: find value of the constant of proportionality in an equation

Q. Out of the following pairs, which one does not have identical dimensions ? Angular momentum and Planck's constantImpulse and momentumMoment of inertia and moment of a forceWork and torque Answer: Moment of inertia and moment of a force

Q. A student measures the distance covered and time taken by a body under free fall which was intially at rest. He uses this data for estimating g, the acceleration due to gravity. If the maximum percentage error in measurement of the distance and the time are e1 and e2 respectively, then the ...

Q. Identify the pair whose dimensions are equal. Torque and workStress and energyForce and stressForce and work Answer: Torque and work

Q. In the above question dimensions of b/c are the same as those of Wave velocityWavelengthWave amplitudeWave frequency Answer: Wave velocity

Q. Unit for a fundamental physical quantity is defined as best of various reference standardsthe smallest measurable value of the physical quantitydefined as average various reference standardsreference standard for the physical quantity Answer: reference standard for the physical quantity

Q. One second is defined to be equal to 9192631770 periods of the cesium clock1650763.73 periods of the cesium clock652189.63 periods of the krypton clock1650763.73 periods of the krypton clock Answer: 9192631770 periods of the cesium clock

Q9. In a system of units if force (F), acceleration (A) and time (T) are taken as fundamentals units then the dimensional formula of energy is FA2TFAT2FA2TFAT Answer: FAT2

Q. Which of the following is a dimensional constant? Gravitational constantDielectric constantRefractive indexRelative density Answer: Gravitational constant

Q. Which of the following physical quantities has different dimensions? EnergyWatt hourMomentumWork Answer: Momentum

Q. Two physical quantities whose dimensions are not same, cannot be multiplied with each otherdividedadded or substracted in the same expressionadded together Answer: added or substracted in the same expression