An ideal fluid flows through a pipe of circular cross-section made of two sections with diameters \(2.5\) cm and \(3.75\) cm. The ratio of the velocities in the two pipes is:
1. \(9:4\)
2. \(3:2\)
3. \(\sqrt{3}:\sqrt{2}\)
4. \(\sqrt{2}:\sqrt{3}\)
The angle of contact at the interface of the water glass is \(0^{\circ},\) ethyl-alcohol glass is \(0^{\circ},\) mercury-glass is \(140^{\circ}\) and methyl iodide-glass is \(30^{\circ}.\) A glass capillary is put in a trough containing one of these four liquids is observed that the meniscus is convex. The liquid in the trough is:
1. water
2. ethyl alcohol
3. mercury
4. methyl iodide
For a surface molecule,
(a) | The net force on it is zero. |
(b) | There is a net downward force. |
(c) | The potential energy is less than that of a molecule inside. |
(d) | The potential energy is more than that of a molecule inside. |
Choose the correct alterative/s:
1. | (b), (c) | 2. | (b), (d) |
3. | (c), (d) | 4. | (a), (d) |
Pressure is a scalar quantity because:
(a) | it is the ratio of force to the area and both force and area are vectors. |
(b) | it is the ratio of the magnitude of the force to the area. |
(c) | it is the ratio of the component of the force normal to the area. |
(d) | it does not depend on the size of the area chosen. |
Choose the correct alterative/s:
1. | (b), (c) | 2. | (a), (d) |
3. | (b), (d) | 4. | (c), (d) |
A wooden block with a coin placed on its top, floats in water as shown in the figure.
The distances \(\mathrm{l}\) and \(\mathrm{h}\) are shown in the figure. After some time, the coin falls
into the water. Then,
(a) | \(\mathrm{l}\) decreases |
(b) | \(\mathrm{h}\) decreases |
(c) | \(\mathrm{l}\) increases |
(d) | \(\mathrm{h}\) increases |
Choose the correct alterative/s:
1. | (b), (c) |
2. | (a), (d) |
3. | (c), (d) |
4. | (a), (b) |
(a) | gases decreases. | (b) | liquids increases. |
(c) | gases increases. | (d) | liquids decreases. |
Streamline flow is more likely for liquids with,
(a) | high density. | (b) | high viscosity. |
(c) | low density. | (d) | low viscosity. |
Choose the correct option:
1. | (a), (b) | 2. | (c), (d) |
3. | (b), (c) | 4. | (a), (d) |
Along a streamline,
1. | the velocity of a fluid particle remains constant. |
2. | the velocity of all fluid particles crossing a given position is constant. |
3. | the velocity of all fluid particles at a given instant is constant. |
4. | the speed of a fluid particle remains constant. |
Which of the following diagrams does not represent a streamline flow?
1. | 2. | ||
3. | |
4. | |
A tall cylinder is filled with viscous oil. A round pebble is dropped from the top with zero initial velocity. From the plot shown in the figure, indicate the one that represents the velocity \((v)\) of the pebble as a function of time \((t).\)
1. | 2. | ||
3. | 4. |