QJEEM17Pha7dd: JEE Main 2017 Physics - Class 11 JEEM17Pha7dd Solution: The following observations were taken for determining surface…

Question

Verified Solution • 2025–26 Session moderate

The following observations were taken for determining surface tension T of water by capillary method:
diameter of capillary, D = 1.25

\times

10^-2 m
rise of water, h = 1.45

\times

10^-2m
Using g = 9.80 m/s² and the simplified relation T =

\frac{r h g}{2} \times 10^{3} N / m

, the possible error in surface tension is closest to :

Accepted Answer

Surface tension,

T =

\frac{r h g}{2} \times 10^{3} N / m

Relative error,

\frac{Δ T}{T} = \frac{Δ r}{r} + \frac{Δ h}{h}

Percentage error,

\frac{Δ T}{T} \times 100 = \frac{Δ r}{r} \times 100 + \frac{Δ h}{h} \times 100

\frac{Δ T}{T} \times 100 = (\frac{10^{- 2} \times 0.01}{1.25 \times 10^{- 2}} + \frac{10^{- 2} \times 0.01}{1.45 \times 10^{- 2}}) \times 100

= (0.8 + 0.689) = 1.489 % = 1.5 %

Step-by-Step Verified Solution