JEE MAIN - Physics (2021 - 27th July Evening Shift - No. 14)

A physical quantity 'y' is represented by the formula $$y = {m^2}{r^{ - 4}}{g^x}{l^{ - {3 \over 2}}}$$

If the percentage errors found in y, m, r, l and g are 18, 1, 0.5, 4 and p respectively, then find the value of x and p.
5 and $$\pm$$2
4 and $$\pm$$3
$${{16} \over 3}$$ and $$ \pm {3 \over 2}$$
8 and $$\pm$$ 2

Explanation

$${{\Delta y} \over y} = {{2\Delta m} \over m} + {{4\Delta r} \over r} + {{x\Delta g} \over g} + {3 \over 2}{{\Delta l} \over l}$$

$$18 = 2(1) + 4(0.5) + xp + {3 \over 2}(4)$$

$$ \Rightarrow $$ 8 = xp

By checking from options.

$$x = {{16} \over 3},p = \pm {3 \over 2}$$

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