4
MCQ (Single Correct Answer)
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
A
$9: 4$
B
$3: 2$
C
$\sqrt{3}: \sqrt{2}$
D
$\sqrt{2}: \sqrt{3}$
5
MCQ (Single Correct Answer)
The angle of contact at the interface of water-glass is $0^{\circ}$, ethyl alcohol-glass is $0^{\circ}$, mercury-glass is $140^{\circ}$ and methyliodide-glass is $30^{\circ}$. A glass capillary is put in a trough containing one of these four liquids. It is observed that the meniscus is convex. The liquid in the trough is
A
water
B
ethylalcohol
C
mercury
D
methyliodide
6
MCQ (Multiple Correct Answer)
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
7
MCQ (Multiple Correct Answer)
Pressure is a scalar quantity, because
A
it is the ratio of force to area and both force and area are vectors
B
it is the ratio of the magnitude of the force to 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
8
MCQ (Multiple Correct Answer)
A wooden block with a coin placed on its top, floats in water as shown in figure.
The distance $l$ and $h$ are shown in the figure. After sometime, the coin falls into the water. Then,
A
$l$ decreases
B
$h$ decreases
C
$l$ increases
D
$h$ increases