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

Total Questions: 50

11. Which one of the following methods can be used to remove permanent hardness of water?

(a) Boiling
(b) Ion-exchange
(c) Lime treatment
(d) Bubbling sulphur dioxide gas

Correct Answer: (b) Ion-exchange

Solution:The permanent hardness of water is due to the presence of chlorides, nitrates and sulphates of calcium and magnesium in the water. There are various methods of removal of this hardness as simple methods like boiling. lime treatment, Permanent hardness can be removed by Ion Exchange Resin Method, Gan's Permutit Method.

Calgon's Process, etc. But bubbling SO, cannot help in the removal of permanent hardness. Thus, options a, b, and c are correct and option D is incorrect.

12. Which one of the following is NOT a component of photochemical smog?

(a) Ozone
(b) Peroxyacetyl nitrate
(c) Polyaromatic hydrocarbons
(d) Nitric oxide

Correct Answer: (c) Polyaromatic hydrocarbons

Solution:Polyaromatic hydrocarbons are not one of the components of Photochemical smog. When oxides of nitrogen are exposed to ultraviolet radiation they undergo a complex series of hydrocarbon reactions to produce the photochemical smog components. These components include a mixture of ozone, aldehydes, nitric acid, peroxyacyl nitrates and many other secondary pollutants.

13. The eukaryotic chromatin is composed of

(a) DNA only
(b) DNA and Protein
(c) DNA and RNA
(d) RNA and Protein

Correct Answer: (b) DNA and Protein

Solution:The eukaryotic chromatin is composed of DNA and protein. Chromatin is a highly organized complex of DNA and proteins and is a principal component of the cell nucleus. It helps in the organization or packaging of DNA inside the nucleus.

14. In which of the following phylum, would you place an animal with a bilaterally symmetrical, triploblastic body without a true internal cavity (coelom)?

(a) Porifera
(b) Platyhelminthes
(c) Cnidaria
(d) Annelida

Correct Answer: (b) Platyhelminthes

Solution:The animal with bilateral symmetry and triploblastic body without true coelom is placed in the phylum Platyhelminthes. These are commonly known as flatworms. Flatworms have no body cavity other than the gut and lack an anus and use pharyngeal opening for both intake of food as well as waste excretion.

15. During respiration in human beings, the actual place of gaseous exchange is

(a) Bronchi
(b) Nasal passage
(c) Alveoli
(d) Trachea

Correct Answer: (c) Alveoli

Solution:The actual site of gaseous exchange in the human respiratory system is alveoli. Here exchanges of gases take place between alveoli and blood capillaries by oxygen entering the bloodstream and carbon dioxide exiting. It is through this mechanism that blood is oxygenated and carbon dioxide, the waste product of cellular respiration, is removed from the body.

16. In human body, the hormone which is secreted into blood and which controls the rate of heart beat is

(a) Adrenaline
(b) Thyroxine
(c) Insulin
(d) Testosterone

Correct Answer: (a) Adrenaline

Solution:Adrenaline is a stress hormone that is produced within the adrenal gland and secreted into the blood. It alters the heartbeat, strengthens the force of the heart's contraction and opens up the bronchioles in the lungs.

17. In human beings, certain chemicals which cross the synapse between nerve cells are released from

(a) cell body of nerve cell
(b) nucleus of nerve cell
(c) nerve endings of nerve cell
(d) axon of nerve cell

Correct Answer: (c) nerve endings of nerve cell

Solution:The chemical which crosses the synapse between nerve cells is released from the nerve endings of nerve cells. The arrival of a nerve impulse at the presynaptic terminals causes the movement toward the presynaptic membrane of membrane-bound sacs, or synaptic vesicles, which fuse with the membrane and release a chemical substance called a neurotransmitter.

18. 18. Which one of the following is the major function of platelets?

(a) Clotting of blood
(b) O, transport
(c) Immunity
(d) Phagocytosis

Correct Answer: (a) Clotting of blood

Solution:The major function of Platelets or thrombocytes is blood clotting. If a blood vessel wall becomes damaged, platelets help in cot formation at the site of damage. Platelets stop blood loss by clotting and clogging arteries.

19. An electron and a photon have same de Broglie wavelength. It implies that they have the same

(a) linear momentum
(b) energy
(c) speed
(d) angular momentum

Correct Answer: (a) linear momentum

Solution:As per de Broglie equation λ=h/p or in the question it is given that both electrons and the photons have the same
De Broglie wavelength,
therefore for electrons, De Broglie wavelength
λε = h/p

For Photon, λp = h/p this means if h (Planck's constant), the wavelength is the same then the linear momentum (p) must be the same hence, if electrons and the photons have the same De Broglie wavelength they both have the same linear momentum.

20. Oil and water do NOT mix because of the property of

(a) bulk modulus
(b) shear strain
(c) volume effect
(d) surface tension

Correct Answer: (d) surface tension

Solution:Oil has a surface tension of 35 dynes/cm while water gas is 72 dynes/cm. Due to this large variation between this Water and oil do not mix.

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