CAPF (AC) 2020 (Paper-1) (Question 1-50)

Total Questions: 50

21. At triple point the substance co-exists in

1. Liquid phase

2. Solid phase

3. Vapour phase

Select the correct answer using the code given below :

Correct Answer: (d) 1, 2 and 3
Solution:

The triple point of a substance is the temperature and pressure at which all the three phases that are gas, liquid, and solid of that substance coexist in thermodynamic equilibrium.

A system is said to be in thermodynamic equilibrium when the following three conditions of equilibrium are satisfied simultaneously: mechanical equilibrium, chemical equilibrium, and thermal equilibrium.

Mechanical equilibrium: For a system to be in mechanical equilibrium, there should not be any unbalanced forces acting within the system and between the system and its surrounding. Also, the pressure in the system should be the same throughout the system and should not change with time.

Chemical equilibrium: For a system to be in chemical equilibrium there should be no chemical reactions going on within the system. There is no transfer of matter from one part of the system to the other due to diffusion. A system to be in chemical equilibrium its chemical composition has to be the same throughout and should not change with time.

Thermal equilibrium: For a system to be in thermal equilibrium, the temperature of the system should be uniform throughout and it should not change with time. A system when in thermal equilibrium is described in terms of state variables.

22. Latent heat corresponds to the change in heat at constant

Correct Answer: (a) temperature only
Solution:

Latent heat is the energy released or absorbed by a body or a thermodynamic system during a constant-temperature process. In the process, the temperature remains constant.

  • When substances transform from one state to another, they absorb or release energy. Part of this heat energy is utilized to overcome the forces of attraction between the molecules, and it is referred to as latent heat.
  • It's evident that knowing how much energy it takes to change the state of a substance’s unit mass is useful. This is referred to as “specific latent heat,” and it is defined as follows:
  • The energy required to change the state of 1 kg of a substance is known as specific latent heat.
  • What should be kept in mind about latent heat is that in a closed system, the temperature of the system remains constant. It is only referring to the extra energy that is expelled or absorbed when the transition occurs.

23. Which one of the following statements on photoelectric effect is NOT correct?

Correct Answer: (c) At a frequency v > v₀, the kinetic energy of ejected . electrons does not change on increasing the frequency of incident light
Solution:

In the Photoelectric effect, above a threshold value of v > v₀, the kinetic energy of the electrons is linearly proportional to the frequency of the incident radiation. The number of electrons however is proportional to the light intensity.

What is Kinetic Energy?

Kinetic energy is the energy an item has on account of its movement.

If we desire to speed up an article, we should apply power. Applying power expects us to take care of business. After work has been done, energy has been moved to the particle, and the item will be moving with another steady speed. The energy moved is known as Kinetic
energy, and it relies upon the mass and speed accomplished.

Kinetic energy can be moved among objects and changed into different sorts of energy. For instance, a flying squirrel could crash into a fixed chipmunk. Following the impact, a portion of the underlying active energy of the squirrel could have been moved into the chipmunk
or changed to another type of energy.

24. Which one of the following is the average atomic mass of chlorine atom?

Correct Answer: (b) 35.5 u
Solution:

The average Atomic mass of Chlorine is 35.5u. The Average atomic mass is calculated to don the basis of two isotopes of chlorine along with their per cent abundances in nature.

chlorine-35: atomic mass = 34.969 amu and percentage abundance = 75.77%

chlorine-37: atomic mass = 36.966 amu and percentage abundance = 24.23%

The individual atomic mass of chlorine-35 is 0.7577 × 34.969-26.50 amu and of

chlorine-37 is 0.2423 × 26.966 = 8.957 amu.

The average atomic mass will be 26.50 + 8.957 = 35.5 amu

25. Which one of the following is NOT a heterocyclic aromatic compound?

Correct Answer: (a) Tropolone
Solution:

Cyclic Aromatic compounds containing one or more heteroatoms in their rings are called heterocyclic aromatic compounds. Atoms other than C and H are known as heteroatoms. Furan (C4H4O), Thiophene (C4H4S) and Pyridine (C5H5N) are heterocyclic aromatic compounds. Troplone is not a heterocyclic aromatic compound.

26. Which one of the following minerals is NOT a naturally occurring silicate?

Correct Answer: (d) Bauxite
Solution:

Feldspar, Mica, and Zeolites are naturally occurring Silicates. Zeolites can also be synthetic. Bauxite is a naturally occurring, heterogeneous material composed primarily of aluminium hydroxide. It is not a naturally occurring silicate.

27. In which part of the cell, the glucose is converted into pyruvate?

Correct Answer: (c) Cytoplasm
Solution:

Glucose is converted into pyruvate in the cytoplasm of the cell. This conversion takes place through the process known as glycolysis. Glycolysis is used by all cells in the body for energy generation.

Glycolysis is the primary step of cellular respiration, which occurs in all organisms. Glycolysis is followed by the Krebs cycle during aerobic respiration. In the absence of oxygen, the cells make small amounts of ATP as glycolysis is followed by fermentation.

Key Points of Glycolysis

  • It is the process in which a glucose molecule is broken down into two molecules of pyruvate.
  • The process takes place in the cytoplasm of plant and animal cells.
  • Sixenzymes are involved in the process.
  • The end products of the reaction include 2 pyruvate, 2 ATP and 2 NADH molecules.

28. After fertilization, the ovule and ovary subsequently develop to form

Correct Answer: (a) seed and fruit respectively
Solution:Fertilization is the process of fusion of the male gametes (pollen) with the female gametes (ovum) to form a diploid zygote. It is a physicochemical process that occurs after pollination. After fertilization, the Ovary is converted into fruit and the ovule is converted into seeds.

29. Which one of the following statements is correct?

Correct Answer: (c) Glucose breaks down into CO₂, H₂O and energy in all aerobic tissues
Solution:In all aerobic cells of the body, the glucose is broken down to give rise to Carbon dioxide, water and energy in the form of ATP. The stages of cellular respiration are glycolysis which is an anaerobic process. Aerobic steps involve the Krebs cycle and oxidative phosphorylation.

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP

30. Growing two or more crops in the same field but in different rows is called

Correct Answer: (b) Inter cropping
Solution:

In Intercropping two or more crops are grown in the same field in alternate rows. The most common goal of intercropping is to produce a greater yield on a given piece of land by making use of resources or ecological processes.

  • Intercropping is a method of increasing agricultural productivity by planting two or more crops simultaneously on a specific plot of land in a specific row pattern.
  • The primary goal of this type of cropping is to make use of the space between two rows of main crop and produce more grain per unit area.
  • Small farmers who depend on rain for higher production are more likely to use it.
  • This procedure has a specific row pattern, such as 1:1 or 1:2, which means that the primary crop is in the first row and the other crops are in the second or third row.
  • These crops are blended in this technique despite having different nutrient needs. It guarantees the best possible use of the nutrients given.
  • Additionally, it stops pests and diseases from spreading to every plant involved in a particular crop.