JEE Main 2017 · 2 Apr · Shift 1 · Physics Q30

← JEE Main 2017 · 2 Apr · Shift 1

PhysicsSingle correct+4 / -1Question 30 of 90

The following observations were taken for determining surface tension T of water by capillary method :

diameter of capillary, $D=1.25\times10^{-2}$ m

rise of water, $h=1.45\times10^{-2}$ m.

Using $g=9.80$ m/s $^2$ and the simplified relation $T=\dfrac{rhg}2\times10^3$ N/m, the possible error in surface tension is closest to :

0.15%

1.5%

2.4%

10%

Answer and worked solution

Official answer: B

$T\propto rhg$ , so
$\frac{\Delta T}T=\frac{\Delta r}r+\frac{\Delta h}h+\frac{\Delta g}g=\frac{0.01}{1.25}+\frac{0.01}{1.45}+\frac{0.01}{9.80}=0.80\%+0.69\%+0.10\%\approx1.6\%,$
closest to 1.5%.

Topics:Errors in experiments Capillarity

← Previous question Next question →

JEE Main 2017 · 2 Apr · Shift 1, Physics question 30