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QJEEM21Ph2b14: JEE Main 2021 Physics - Class 11 JEEM21Ph2b14 Solution: The acceleration due to gravity is found upto an accuracy of 4% …

The acceleration due to gravity is found upto an accuracy of 4% on a planet. The energy supplied to a simple pendulum to known mass 'm' to undertake oscillations of time period T is being estimated. If time period is measured to an accuracy of 3%, the accuracy to which E is known as ..............%

Step-by-Step Verified Solution

T=2πlg⇒l=T2g4π2T = 2\pi \sqrt {{l \over g}} \Rightarrow l = {{{T^2}g} \over {4{\pi ^2}}}

E=mglθ22=mg2T2θ28π2E = mgl{{{\theta ^2}} \over 2} = m{g^2}{{{T^2}{\theta ^2}} \over {8{\pi ^2}}}

dEE=2(dgg+dTT){{dE} \over E} = 2\left( {{{dg} \over g} + {{dT} \over T}} \right)

=(4+3)=14%= (4 + 3) = 14\%

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