Suppose the pressure at the surface of mercury in a barometer tube is P1 and the pressure at the surface of mercury in the cup is P2.
1. P1 = 0, P2 = atmospheric pressure
2. P1 = atmospheric pressure, P2 = 0
3. P1 = P2 = atmospheric pressure
4. P1 = P2 = 0
A barometer kept in an elevator reads 76 cm when it is at rest. If the elevator goes up with increasing speed, the reading will be
1. zero
2. 76 cm
3. < 76 cm
4. > 76 cm
A barometer kept in an elevator accelerating upward reads 76 cm. The air pressure in the elevator is
1. zero
2. 76 cm
3. < 76 cm
4. > 76 cm
To construct a barometer, a tube of length 1 m is filled completely with mercury and is inverted in a mercury cup. The barometer reading on a particular day is 76 cm. Suppose a 1 m tube is filled with mercury up to 76 cm and then closed by a cork. It is inverted in a mercury cup and the cork is removed. The height of mercury column in the tube over the surface in the cup will be
1. zero
2. 76 cm
3. > 76 cm
4. < 76 cm
A \(20\) N metal block is suspended by a spring balance. A beaker containing some water is placed on a weighing machine which reads \(40\) N. The spring balance is now lowered so that the block gets immersed in the water. The spring balance now reads \(16\) N. The reading of the weighing machine will be:
1. \(36\) N
2. \(60\) N
3. \(44\) N
4. \(56\) N
A piece of wood is floating in water kept in a bottle. The bottle is connected to an air pump. Neglect the compressibility of water. When more air is pushed into the bottle from the pump, the piece of wood will float with
1. larger part in the water
2. lesser part in the water
3. same part in the water
4. it will sink
A metal cube is placed in an empty vessel. When water is filled in the vessel so that the cube is completely immersed in the water, the force on the bottom of the vessel in contact with the cube:
1. will increase
2. will decrease
3. will remain the same
4. will become zero
1. | \(P_1=P_2=P_3\) | 2. | \(P_1<P_2<P_3\) |
3. | \(P_1=P_2\neq P_3\) | 4. | \(P_2=P_3\neq P_1\) |
A closed cubical box is completely filled with water is accelerated horizontally towards right with an acceleration a. The resultant normal force by the water on the top of the box:
1. passes through the centre of the top.
2. passes through a point to the right of the centre.
3. passes through a point to the left of the centre.
4. becomes zero.
Consider the situation of the previous problem. Let the water push the left wall by a force F1 and the right wall by a force F2
1. F1 = F2
2. F1 > F2
3. F1 < F2
4. The information is insufficient to know the relation between F1 and F2
Previous problem: A closed cubical box is completely filled with water is accelerated horizontally towards right with an acceleration a.