Physics
##### ASSERTION

The error in the measurement, of radius of the sphere is $0.3$% . The permissible error in its surface area is $0.6$%

##### REASON

The permissible error is calculated by the formula $\dfrac {\Delta A}{A} = \dfrac {4\Delta r}{r}$

Assertion is correct but Reason is incorrect

##### SOLUTION

Area of the sphere, $A = 4\pi r^{2}$

% error in area $= 2 \times$ % error in radius

i.e., $\dfrac {\Delta A}{A} \times 100 = 2\times \dfrac {\Delta r}{r} \times 100$

$= 2\times 0.3$ % $= 0.6$%

But $\dfrac {\Delta A}{A} = 4 \dfrac {\Delta r}{r}$ is false.

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Assertion & Reason Hard Published on 18th 08, 2020
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Subjects 8
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