A air bubble of radius 1cm in water has an upward acceleration of 9.8 cms ^ – 2 . The density of water is 1 gm cm ^ – 3 and water offers negligible drag force on the bubble. The mass of the bubble is (g = 980cm / s ^ 2

Correct answer: C. 4.15gm F _ b - mg = ma F _ b = m(g + a) = (4)/(3) π r ^ 3 ρg = m(g + a) m = (4)/(3)π(1)g = m(980 + 9 .8) m = 4 . 15

JEE Main 20204 SeptemberMorning Shift

JEE Main 2020 · 4 September · Morning Shift · Physics · Mechanical Properties of Fluids

A air bubble of radius 1cm in water has an upward acceleration of...

A air bubble of radius

1\text{cm}

in water has an upward acceleration of

9.8{\text{cms}}^{– 2}

. The density of water is

1{\text{gm cm}}^{– 3}

and water offers negligible drag force on the bubble. The mass of the bubble is

\left(g = 980\text{cm} / {\text{s}}^{2}\right)

C. $4.15\text{gm}$

${F}_{b} - mg = ma$

${F}_{b} = m\left(g + a\right)$

$= \dfrac{4}{3}{\pi r}^{3}ρg = m\left(g + a\right)$

$m = \dfrac{4}{3}\pi\left(1\right)g = m\left(980 + 9 .8\right)$

$m = 4 . 15$