CBSE
Multiple Choice QuestionsMercury boils at 367° C. However, mercury thermometers are made such that they can measure temperature upto 500°C. This is done by
maintaining vacuum above mercury column in the stem of the thermometer.
filling nitrogen gas at high pressure above the mercury column.
filling oxygen gas at a high pressure above mercury column.
filling nitrogen gas at a low pressure above the mercury column.
Two identical glass spheres filled with air are connected by a horizontal glass tube. The glass tube contains a pellet of mercury at its mid-point. Air in one sphere is at 0°C and the other is at 20°C. If both the vessels are heated through 10°C, then neglecting the expansions of the bulbs and the tube.
the mercury pellet gets displaced towards the sphere at a lower temperature.
The mercury pellet gets displaced towards the sphere at a higher temperature
The mercury pellet does not get displaced at all.
the temperature rise causes the pellet to expand with any displacement.
Water rises in a capillary upto a extension height such that upward force of surface tension balances the force of 75 x 10-4 N due to weight of water. If surface tension of water is 6x10-2 N/m.The internal circumference of the capillary must be
12.5m
6.5m
0.50m
1.25m
A capillary tube of radius r can support a liquid of weight 6.28 x 10-4 N. If the surface tension of the liquid is 5 x 10-2N/m. The radius of capillary must be
m
1.5
The soap bubbles have radii in the ratio 2: 1 ratio of excess pressure in side there is
1:4
4:1
2:1
1:2
The radius R of the soap bubble is doubled under isothermal condition. If T be the surface tension of soap bubble. The work done in doing so is given by
An ice-cube of density 900 kg /m3 is floating in water of density 1000 kg / m3. The percentage of volume of ice-cube outside the water is
20%
35%
10%
25%
A tank is filled with water upto height H. When a hole is made at a distance h below the level of water. What will be the horizontal range of water jet?
A charged oil drop is suspended in uniform field of 3 x 104 V/m so that it neither falls nor rises. The charge on the drop will be (Take the mass of the charge = 9.9 x 10-15 kg and g = 10 m/s2 )
3.3 × 10-18 C
3.2 × 10-18 C
1.6 × 10-18 C
4.8 × 10-18 C
A frame made of metallic wire enclosing a surface area A is covered with a soap film. If the area of the frame of metallic wire is reduced by 50%, the energy of the soap film will be changed by
100%
75%
50%
25%
