JEE Main Physics and Measurement — practice questions
Explore 23 free Physics and Measurement questions in JEE Main Physics. Open each question or exercise to read its content, reference answers and available explanation.
Write quantities with units before calculating. Convert to one unit system, then check the dimensions of the result. Significant figures describe the precision of a measurement; extra calculator digits do not improve it.
Key ideas and when to use them
Speed: $v=\Delta x/\Delta t$; SI unit $\mathrm{m\,s^{-1}}$.
Density: $\rho=m/V$; SI unit $\mathrm{kg\,m^{-3}}$.
Force has dimensions $[M L T^{-2}]$; dimensional agreement is necessary, not proof of an equation.
Common mistakes
Convert areas and volumes using squared and cubed conversion factors.
Keep extra digits during intermediate steps and round the final result.
Three worked examples
Example 1: Convert 54 km/h to m/s.
One kilometre is 1000 m; one hour is 3600 s.
$v=54\times1000/3600$.
15 m/s
Example 2: A sample has mass 540 g and volume 200 cm³. Find its density in SI units.
Convert the mass to 0.540 kg and the volume to $200\times10^{-6}$ m³.
$\rho=0.540/(200\times10^{-6})$.
2700 kg/m³
Example 3: Add a distance of 3.2 km to 200 m. Give the total in metres.
Convert 3.2 km to 3200 m.
Add quantities expressed in the same unit: $3200+200$.
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