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These questions consist of two statement, each printed as assertion and reason. While answering these question you are required to cheese any one of the following five responses.
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 $$\dfrac {\Delta A}{A} = \dfrac {4\Delta r}{r}$$


ANSWER

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
Physics

Assertion: The dimensional formula for relative velocity is same as that of the change in velocity.
Reason: 
Relative velocity of P w.r.t. Q is the ratio of velocity of P and that of Q.


ANSWER

Assertion is true but reason is false


SOLUTION

Relative velocity which is vector subtraction of two velocities will also be a vector of the form of velocity so, its dimensional formula will remain unchanged. Relative velocity is measured not by calculating ratio but by calculating difference.

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Single Correct Hard Published on 18th 08, 2020
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