1
MHT CET 2021 22th September Evening Shift
MCQ (Single Correct Answer)
+1
-0

A needle is $$7 \mathrm{~cm}$$ long. Assuming that the needle is not wetted by water, what is the weight of the needle, so that it floats on water?

$$\left[\mathrm{T}=\right.$$ surface tension of water $$\left.=70 \frac{\mathrm{dyne}}{\mathrm{cm}}\right]$$

[acceleration due to gravity $$=980 \mathrm{~cm} \mathrm{~s}^{-2}$$]

A
1 g wt
B
5 g wt
C
3 g wt
D
7 g wt
2
MHT CET 2021 22th September Morning Shift
MCQ (Single Correct Answer)
+1
-0

Water rises in a capillary tube of radius '$$r$$' up to a height '$$\mathrm{h}$$'. The mass of water in a capillary is '$$\mathrm{m}$$'. The mass of water that will rise in a capillary tube of radius $$\frac{'r'}{3}$$ will be

A
$$3 \mathrm{~m}$$
B
$$\frac{\mathrm{m}}{3}$$
C
$$\mathrm{m}$$
D
$$\frac{2 \mathrm{~m}}{3}$$
3
MHT CET 2021 22th September Morning Shift
MCQ (Single Correct Answer)
+1
-0

A drop of liquid of density '$$\rho$$' is floating half immersed in a liquid of density '$$d$$'. If '$$T$$' is the surface tension, then the diameter of the drop of the liquid is

A
$$\sqrt{\frac{6 \mathrm{~T}}{\mathrm{~g}(2 p-\mathrm{d})}}$$
B
$$\sqrt{\frac{T}{g(2 \rho-d)}}$$
C
$$\sqrt{\frac{2 T}{g(2 p-d)}}$$
D
$$\sqrt{\frac{12 T}{g(2 \rho-d)}}$$
4
MHT CET 2021 21th September Evening Shift
MCQ (Single Correct Answer)
+1
-0

Under isothermal conditions, two soap bubbles of radii '$$r_1$$' and '$$r_2$$' combine to form a single soap bubble of radius '$$R$$'. The surface tension of soap solution is ( $$P=$$ outside pressure)

A
$$\frac{P\left(R^3+r_1^3+r_2^3\right)}{4\left(r_1^2-r_2^2+R^2\right)}$$
B
$$\frac{P^2+r_1^2+r_2^2}{4\left(r_1^2+r_2^2+R^2\right)}$$
C
$$\frac{P\left(R^3-r_1^3-r_2^3\right)}{4\left(r_1^2+r_2^2-R^2\right)}$$
D
$$\frac{P\left(R^2-r_1^2-r_2^2\right)}{4\left(r_1^3+r_2^3-R^3\right)}$$
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