1.
Type short note on Real Gases and Ideal Gases
2.
The choice of thermometric liquids in a thermometer should depend on the following properties except:
Correct Answer
B. Must have a high specific heat capacity
Explanation
1. It must be opaque
2. It must have uniform expansion and contraction
3. It must have a high boiling point
4. It must have a low freezing (melting) point
5. It must not "wet" the glass .i.e should not stick to the glass due to cohesive forces
All these are also the reason why water isn't used as a thermometric liquid
3.
A platinum resistance thermometer has resistance of 52.5 ohms and 9.75 ohms at 0 degrees Celsius and 100 degrees Celsius respectively. When the resistance is 8.25 ohms, find the temperature
Correct Answer
C. 66:7oC
Explanation
Resistance of 52.5 ohms and 9.75 ohms
at 0 oC and 100oC respectively,
at 8.25 ohm find ToC
using
(T-0) = (8.25 - 5.25)
(100-0) (9.75 - 5.25)
ToC = 66.7oC (B)
4.
Which of the following types of bench would feel warmer on a cool harmattan day?
Correct Answer
A. Wood
Explanation
Aluminium,
marble and
iron
have a large thermal mass and conduct heat readily, if they are already cool from the surroundings, they will extract heat from your hand and feel cool.
Wood
has a low thermal mass and is a poor conductor of heat, so the surface will warm up quickly when you touch it and the object will feel warmer
5.
Is real gases the same as an Ideal gases
Correct Answer
B. False
Explanation
An ideal gas is made up of particles that are single points with no volume. This means that the atoms or molecules take up absolutely no room. Real gases are made up of atoms or molecules that actually take up some space, no matter how small.
An ideal gas is made up of particles that do not attract or repel one another. Real gases are made up of atoms or molecules that may attract one another strongly, like ammonia, water vapor, or sulfur dioxide. Or they may attract one another hardly at all, like helium.
Real gases behave like ideal gases at "ordinary" temperatures and pressures. But if you heat them up and compress them to high pressure, then their behavior departs from ideal.
6.
Which of the following explains why we feel cool when we stay very close to a fan?
Correct Answer
D. Evaporation
Explanation
Evapoaration is the process by which water is converted from its liquid form to its vapor form and thus transferred from land and water masses to the atmosphere
7.
One of these is NOT a factor that can affect the rate of evaporation
Correct Answer
C. Volume of liquid
Explanation
                 FACTORS THAT AFFECT THE RATE OF EVAPORATION
1. Wind assists evaporation; for example in clothes dry faster under a fan.
2. Heat assists evaporation; for example, in summer clothes dry faster than in winter.
3. Increase in surface area exposed assists evaporation; for instance, a wet cloth spread out dries faster than when folded.
4. Dryness assists evaporation; for instance, clothes dry faster in summer than during the monsoon when the air is humid.
5. Rate of evaporation depends upon the nature of the liquid; for example, petrol evaporates faster than water.
6. Vapor pressure: if pressure is applied on the surface of a liquid, evaporation is hindered; consider, for example, the case of a pressure cooker.
8.
Which of the following is NOT a method of transporting heat energy from one place to another
Correct Answer
A. Condensation
Explanation
Heat energy is always transported (transferred) from a hotter object to a colder object. This can happen in one of three ways -- by conduction, by convection or by radiation
9.
Avogadro suggested that each liter of gas under identical conditions has the same
Correct Answer
C. Number of molecules
Explanation
Avogadro's law states that, "equal volumes of all gases, at the same temperature and pressure, have the same number of molecules.
10.
If 1 liter of oxygen combines completely with 2 liters of hydrogen to form water, how many liters of oxygen are required to combine completely with 8 liters of hydrogen?
Correct Answer
C. 4
Explanation
To form water, 1 liter of oxygen combines completely with 2 liters of hydrogen. Therefore, if we have 8 liters of hydrogen, we would need 4 liters of oxygen to completely combine with it, as 4 liters of oxygen would be enough to combine with 8 liters of hydrogen.
11.
The atomic mass of carbon dioxide is 44 atomic mass units. What is the atomic mass of oxygen if each molecule contains one atom of carbon and two of oxygen?
Correct Answer
D. 16
Explanation
Each molecule of carbon dioxide contains one atom of carbon and two atoms of oxygen. The atomic mass of carbon is 12 atomic mass units, and the atomic mass of oxygen is 16 atomic mass units. Therefore, the total atomic mass of the two oxygen atoms in a molecule of carbon dioxide is 2 * 16 = 32 atomic mass units.
12.
The Kelvin temperature scale has the same size degree as the_____ scale and its zero is _____ degrees lower.
Correct Answer
C. Celsius ... 273
Explanation
The Kelvin temperature scale has the same size degree as the Celsius scale and its zero is 273 degrees lower.
13.
Which of the following doubles with a doubling of the Celsius temperature of an ideal gas?
Correct Answer
D. None of the above
Explanation
The average momentum, average speed, and average kinetic energy of an ideal gas do not double with a doubling of the Celsius temperature. The average momentum of an ideal gas is directly proportional to the square root of the temperature, the average speed is directly proportional to the square root of the temperature, and the average kinetic energy is directly proportional to the temperature. Therefore, none of these quantities double when the Celsius temperature of an ideal gas doubles.
14.
What Kelvin temperature corresponds to room temperature of 20 degrees Centigrade
Correct Answer
A. 20 K
Explanation
For more explanation call Mr. Albert 08032688639
15.
Two gases are kept at the same temperature. If the molecules of gas A have 4 times the mass of those of gas B, what is the ratio of the rms speed of the A molecules to that of the B molecules?
Correct Answer
B. 1/2
Explanation
The ratio of the rms speed of the A molecules to that of the B molecules is 1/2. This is because the rms speed of gas molecules is directly proportional to the square root of their mass. Since the molecules of gas A have 4 times the mass of those of gas B, the square root of the mass ratio is 2. Therefore, the ratio of the rms speed of A molecules to B molecules is 1/2.
16.
The mass of an oxygen molecule is 16 times that of a hydrogen molecule. If the gases are maintained at the same temperature, what is the ratio of the rms speed of an oxygen molecule to that ofa hydrogen molecule?
Correct Answer
B. 1/4
Explanation
The ratio of the rms speed of an oxygen molecule to that of a hydrogen molecule is 1/4. This is because the rms speed of a gas molecule is inversely proportional to the square root of its mass. Since the mass of an oxygen molecule is 16 times that of a hydrogen molecule, the rms speed of the oxygen molecule would be 1/4 times that of the hydrogen molecule.
17.
Four liters of an ideal gas is heated from 200 K to 400 K in a container with a fixed volume. If the initial pressure was 1 atm, what is the final pressure?
Correct Answer
C. 2 atm
Explanation
When an ideal gas is heated at a fixed volume, the relationship between pressure and temperature is described by the ideal gas law equation: PV = nRT, where P is the pressure, V is the volume, n is the number of moles of gas, R is the ideal gas constant, and T is the temperature in Kelvin. In this case, the volume is fixed, so we can simplify the equation to P1/T1 = P2/T2. Plugging in the given values, we get P1/200 = P2/400. Solving for P2, we find that P2 = 2 atm. Therefore, the final pressure is 2 atm.
18.
What is the force that binds atoms together?
Correct Answer
B. Electric
Explanation
Electric force is the force that binds atoms together. Atoms consist of positively charged protons and negatively charged electrons. The electric force between these charged particles holds the atoms together in a stable arrangement. This force is responsible for the formation of chemical bonds between atoms, such as covalent and ionic bonds. Gravitational force, magnetic force, and nuclear force do not play a significant role in binding atoms together.
19.
What is the force that binds materials together?
Correct Answer
A. Electric
Explanation
Electric force is the force that binds materials together. This force is responsible for holding atoms and molecules together, creating chemical bonds. It is caused by the attraction between positively charged protons and negatively charged electrons. Electric force is essential for the stability and integrity of materials, allowing them to maintain their structure and form. Without electric force, materials would not be able to exist in their solid or liquid states.
20.
If a block of material has a mass of 8 grams and a volume of 4 cubic centimeters, what is its density?
Correct Answer
D. 2 grams per cubic centimeter
Explanation
The density of a material is calculated by dividing its mass by its volume. In this case, the mass of the block is 8 grams and its volume is 4 cubic centimeters. Dividing the mass by the volume gives us a density of 2 grams per cubic centimeter.
21.
Which of the following effects is NOT a result of surface tension?
Correct Answer
A. The pressure increases with the depth in a fluid
Explanation
Surface tension is a contractive tendency of the surface of a liquid that allows it to resist an external force. It is revealed, for example,
EXAMPLES/EFFECTS OF SURFACE TENSION
in the floating of some objects on the surface of water, even though they are denser than water, and
in the ability of some insects (e.g. water striders) to run on the water surface. This property is caused by cohesion of similar molecules, and is responsible for many of the behavioUrs of liquids.
Soap films on wire frames have minimal surface areas
Liquids floating in the Space Shuttle form into spheres
A glass can be filled with milk beyond its brim.
Surface Tension Examples
Walking on water
Small insects such as the water stridercan walk on water because their weight is not enough to penetrate the surface.
Floating a needle
If carefully placed on the surface, a small needle can be made to float on the surface of water even though it is several times as dense as water. If the surface is agitated to break up the surface tension, then needle will quickly sink.
Don't touch the tent!
Common tent materials are somewhat rainproof in that the surface tension of water will bridge the pores in the finely woven material. But if you touch the tent material with your finger, you break the surface tension and the rain will drip through.
Soaps and detergents
help the cleaning of clothes by lowering the surface tension of the water so that it more readily soaks into pores and soiled areas.
Clinical test for jaundice
Normal urine has a surface tension of about 66 dynes/cm but if bile is present (a test for jaundice), it drops to about 55. In the Hay test, powdered sulfur is sprinkled on the urine surface. It will float on normal urine, but sink if the S.T. is lowered by the bile.
Washing with cold water
The major reason for using hot water for washing is that its surface tension is lower and it is a better wetting agent. But if the detergent lowers the surface tension, the heating may be unneccessary.
Surface tension disinfectants
Disinfectants are usually solutions of low surface tension. This allow them to spread out on the cell walls of bacteria and disrupt them. One such disinfectant, S.T.37, has a name which points to its low surface tension compared to the 72 dynes/cm for water.
Can you think of another?
22.
On a day when the mercury column in a barometer on top of a mountain stands 50 cm tall, how highwould the column in a water barometer be? The density of mercury is 13.6 times that of water.
Correct Answer
D. 680 cm
Explanation
Since static fluid pressure is determined by the fluid density and depth, the depth or height difference of a given liquid is commonly used for pressure measurement:
23.
In which direction in a fluid at rest is the pressure the greatest at a given depth?
Correct Answer
D. The pressure is the same in all directions
Explanation
In a fluid at rest, the pressure is the same in all directions at a given depth. This is because the pressure in a fluid is determined by the weight of the fluid above it, and this weight is evenly distributed in all directions. Therefore, the pressure at a given depth is equal in all directions, whether upward, downward, or horizontal.
24.
Which of the following effects is NOT a result of surface tension?
Correct Answer
C. The pressure increase with the depth in a fluid
Explanation
The pressure increase with the depth in a fluid is not a result of surface tension. Surface tension is the force that causes the surface of a liquid to behave like a stretched elastic sheet. It is responsible for effects such as a glass being filled with milk beyond its brim, liquids floating in the Space Shuttle forming into spheres, and soap films on wire frames having minimal surface areas. However, the pressure increase with depth in a fluid is a result of the weight of the fluid above pushing down, not surface tension.
25.
Two barometers are made with water and oil. The density of oil is 900 kg/m3 and that of water is 1000 kg/m3. If the oil column is 10 m tall, how tall is the water column?
Correct Answer
C. 9.0 m
Explanation
The height of the water column can be determined using the concept of pressure. The pressure at the bottom of the oil column is equal to the pressure at the bottom of the water column. Since pressure is equal to the product of density, gravity, and height, we can set up the equation: (density of oil) x (gravity) x (height of oil column) = (density of water) x (gravity) x (height of water column). By rearranging the equation, we can solve for the height of the water column, which is 9.0 m.
26.
You have two cubes of the same size, one made of aluminum and the other of lead. Both cubes are allowed to sink to the bottom of a water-filled aquarium. Which cube, if either, experiences the greater buoyant force?
Correct Answer
A. The aluminum cube
Explanation
The aluminum cube experiences the greater buoyant force because buoyant force depends on the density of the object. Aluminum has a lower density than lead, so it displaces more water and experiences a greater upward force.
27.
Three spheres have the same mass and all float in water. Spheres A, B, and C have volumes of 2 cm3, 25 cm3, and 30 cm3, respectively. Which sphere floats the highest?
Correct Answer
C. C
Explanation
The sphere that floats the highest is sphere C because it has the largest volume. When an object is placed in a fluid, it displaces an amount of fluid equal to its own volume. The buoyant force acting on an object is equal to the weight of the fluid it displaces. Since spheres A, B, and C all have the same mass, the sphere with the largest volume will displace the most fluid and experience the greatest buoyant force, causing it to float the highest.
28.
Type question here
Correct Answer
A. Answer option 1