Explanation
Steam at 100oC contains extra 540 calorie/gm energy as compare to water at 100oC. So, its more dangerous to burn with steam than water.
We know that when solid carbondioxide is heated, it becomes vapour directly without passing through its liquid phase. Therefore, it is called dry ice.
W = JQ = 4.18 x 400 = 1672 J
Calorimeters are made by conducting materials.
Triple point of water is 273.16 K.
When the relative humidity is low (approx. 25%), the evaporation from our body is faster. Thus we feel colder.
The temperature of land rises rapidly as compared to sea because of specific heat of land is five times less than that of sea water. Thus, the air above the land becomes hot and light so rises up so pressure drops over land. To compensate the drop of pressure, the cooler air from sea starts blowing towards lands, setting up sea breeze. During night land as well sea radiate heat energy. The temperature of land falls more rapidly as compared to sea water, as sea water consists of higher specific heat capacity. The air above sea water being warm and light rises up and to take its place the cold air from land starts blowing towards sea and set up breeze.
For Hooke’s law ; stress ∝ stain i.e. the graph between stress and strain is a straight line, which is so for portion O to D.
When no weight is placed in pan, and T2 shows some value, it means, the pan is not weightness and hence the mass of the pan can not be neglected.
Pressure depends upon the height of liquid column and is independent of area of the surface.
Weight of body = weight of water displaced. so 200 × g = l × l × 2 or l2 = 100 or l = 10 cm
The effective weight of the block in liquid will become less than 2 kg due to buoyancy of liquid. As a result of which A will read less than 2 kg. As the body immersed in liquid has some effective weight acting downwards so the reading of B will be more than 5 kg.
The upward thrust (i.e. buoyancy force) acts on the body and an equal and opposite force acts on the water so the weight will be the sum of the two = 600 + 40 = 640 g.
For water-glass interface, the angle of contact is less than 90o, so the shape of liquid meniscus is concave upwards on both faces.
As excess pressure, p ∝ 1/r, therefore, pressure inside C is highest and pressure inside B is lowest. The pressure inside A is in between. Therefore C starts collapsing with volume of A and B increasing
A membrane has two free surfaces, therefore total force acting on the frame = S.T × boundary of frame × 2 = T × 4 L × 2 = 8 TL
For the given angular velocity of rotation, the centrifugal force F ∝ r ; therefore, more liquid will be accumulated near the wall of tube and the liquid meniscus will become concave upwards.
A molecule in the surface film has maximum pot. energy because the molecule when brought in surface film, the work is done against both gravity and surface tension.
When a solid sphere falls in vacuum, no viscous force is acting on the body and the body falls under gravity. Due to which there will be no terminal velocity of body.
The velocity of a falling body in viscous medium increases with time and finally becomes steady. Hence graph shown in Fig. (d) is correct.
When air streams pass over a curved surface, its speed will be higher than that of flat surface. As a result of which the pressure of air becomes less on curved face than that on flat face. Which will provide a thrust. This thrust is maximum in a wing of a fan shown in fig. (a)
As a solid spherical ball falls from a greater height, it acquires a large velocity before entering the viscous liquid. As it enters liquid, it experiences a viscous drag which opposes its motion. Due to which the velocity of body goes on decreasing. This situation continues till the body attains terminal velocity. At that stage viscous force is balanced by weight of body and net force on body zero. Hence curve (C) is correct.
Since the tubes A and C are connected to tube of same area of cross section, and the liquid flowing there will have same velocity. Hence the height of liquid in A and C will be same. Since tube B is connected to a tube of smaller area of cross-section, therefore the liquid is flowing faster in this tube and pressure there is less according to Bernoulli’s theorem.
When air is blown in the horizontal tube, the pressure of air decreases in the tube. Due to which the water will rise above the tube A.
Horizontal range will be maximum when the hole in the tank lies at the middleof the total height of water surface in tank from ground i.e. h = (2 H + H)/2 = 3 H/2
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