In which of the following is surface tension important?
the floating of a ship in water
the floating of a dry needle in water
the floating of a baloon in air
the diffusion of sugar solution across a membrane
Correct answer is B
A carefully placed small needle can be made to float on the surface of water even though it is several times as dense as water. If the surface is agitated to break up the surface tension, then needle will quickly sink.
1200m
6300m
7500m
13800m
Correct answer is A
Difference in pressure = 75 - 63
= 12cmHg
pressure = hge
difference in height = \(\frac{12}{10 \times \frac{0.00013}{13}}\)
= 1200m
5.0g
12.0g
20.0g
25.0g
Correct answer is C
R.D = \(\frac{\text{ mass of liquid displaced}}{\text {mass of water displaced}}\)
2 = \(\frac{m - 10}{m - 15}\)
m = 20g
15.0cm
17.0cm
20.0cm
23.0cm
Correct answer is D
let the length be Lcm
\(\frac{5 - 3}{25 - L}\) = \(\frac{10 - 5}{30 - 25}\)
L = 23cm
13.3N
73.5N
133.3N
53.2N
Correct answer is C
Efficiency = m.A x \(\frac{1}{V.R}\) X 100%
75 = \(\frac{20 \times 10}{effort}\) x \(\frac{1}{\frac{g}{sin\theta}}\) x 100%
Effort = 133.3N