Explore topic-wise InterviewSolutions in Current Affairs.

Three phases of growth :

i. Meristematic 

ii. Elongation 

iii. Maturation

Drosophila melanogaster is the scientific name of fruit fly. Morgan preferred work with fruit flies because: 

(i) It is grown in simple synthetic medium. 

(ii) It completes the life cycle in only two weeks. 

(iii) It is capable of producing large number of progeny at a time.

Following are essential elements for growth:

• Water for cell enlargement(causes increase in size) and as medium for enzymatic activities.
• Oxygen for release of metabolic energy.
• Nutrients for synthesis of protoplasm & source of energy. 
• Optimum temperature.

Development is the sequence of events that occur in the life history of a cell, organ or organism, which includes growth, differentiation, maturation and senescence.

• Sum of growth and differentiation is called as development. 
• Includes all changes that an organism undergoes throughout life from seed germination to senescence. 
• Development in plants is under control of intrinsic and extrinsic factors. Intrinsic factors include both intracellular (genetic) or intercellular factors (plant growth regulators). Extrinsic factors include light, temperature, water, oxygen, nutrition etc.

1. (a) If both A and R are true and R is correct explanation of A.

2. (d) Both A and R are false.

3. (c) A is true but R is false.

4. (b) If both A and R are true but R is not the correct explanation of A.

5. (c) A is true but R is false.

6. (c) A is true but R is false.

7. (a) If both A and R are true and R is correct explanation of A.

1. False – Tubectomy a method of population control performed on females 

2. False – Oral pills are very popular contraceptives among the urban women 

3. True 

4. True 

5. False – The protective wall of the pollen is exine.

Soyabean is a short day plant : The Pfr form of phytochrome is converted in Pr form by exposure of red light (wavelength 660 nm). The Pfr form is considered as the biologically active form of phytochrome. Germination and other phytochrome controlled processes are promoted by Pfr.

Excessive low-density lipoprotein (LDL) increases the risk of cardio vascular diseases because it causes deposition of cholesterol in blood vessels.

No, omega-3 and omega-6 fats have different effects on the body. 

Omega-3 fats are found to raise the high density lipoprotein, HDL (good cholesterol) level of blood whereas omega-6 fats are considered to increase the risk of high blood pressure.

(c) Sodium lauryl sulphate

(a)  3 2 4 1

(a)  2 4 1 3

• Setting of milk into curd. 
• Raising flour dough to make bread.

[Note: These changes are brought about by action of microorganisms.]

• Primarily the oxygen and microorganisms in air are responsible for adverse effects on stored food. 
• The exposure of stored food to atmosphere is minimized by storing them in air tight container, evacuation or filling the container with N2 gas.
• Rate of a chemical reaction decreases with lowering of temperature. Thus, refrigeration is useful for controlling chemical reaction of foodstuff with environment. 
• The reactions of foodstuff with environment are catalysed by enzymes. Due to boiling, the enzymes become denatured and the reactions are controlled.

Food (like various cereals, pulses, pickles) is stored for a long time to make it available in all seasons.

Correct Answer is: (C) Anti-pyretic 

• The antipyretic analgesics are so named because they combine an analgesic action with the ability to lower body temperature in fever (pyrexia). 

• In fact, most drugs in this group combine analgesic and antipyretic properties with anti-inflammatory properties. 

• Paracetamol is a widely available pain-relieving drug.

Correct Answer is: (A) K₂SO₄

They can be distinguished as follows:

s-block elements: 

(i) They have got the general electronic configuration of the valence shell ns¹⁻² . 

(ii) They are all metals. 

(iii) Their compounds are mostly ionic. 

(iv) They are generally strong reducing agents. 

(v) They mostly impart characteristic colour to the flame. 

(vi) They have low ionisation energies. 

(vii) They show fixed oxidation states.

p-block elements:

(i) The general valence shell electronic configuration of p block elements in ns²p¹⁻⁶ .

(ii) They are mostly non-metals. 

(iii) Their compounds are mostly covalent. 

(iv) They are generally strong oxidizing agents. 

(v) Mostly they do not impart colour to the flame. 

(vi) They have got comparatively higher value of I.E. 

(vii) They show variable oxidation states.

Elements on the extreme of a period easily combine with oxygen to form oxides. The normal oxide formed by the element in extreme left is the most basic (i.e., Na₂O) whereas that formed by the element on extreme right is the most acidic (i.e., Cl₂O₇). Oxides of elements in the centre are amphoteric (e.g., Al₂O₃, As₂O₃) or natural (e.g., CO, NO, N₂O).

As we known that ionization energy increases from left to right in a period so, IE of N > IE of C this is due to decrease in atomic radius.

Electronic configuration of ₇N = 2,5

= 1s² , 2s² , 2p⁶

Electronic configuration of ₈O = 2,6

= 1s² , 2s² , 2p⁴

Since, nitrogen has stable electronic configuration due to presence of half-filled 2p-orbital. So, more energy is required to remove an electron in case of nitrogen than oxygen. So, I.E. of N > I.E. of O

Hence, I.E. of nitrogen is more than 'O and ‘C’ both.

(ii) halogens

(a) The most reactive non-metal has high Δ_i H₁ and Δ_i H₂ and most negative ∆eg H Hence, the most reactive non-metal is I.

(b) The least reactive non-metal has low Δ_i H₁ and Δ_i H₂ and less negative Δ_egH. Hence, the least reactive non-metal is II.

(c) The least reactive element has very high Δ_i H₁ and Δ_i H₂ and has positive Δ_egH values. Hence, the least reactive element is III.

The number designation of a group that has two electrons beyond a noble gas configuration will be two which means it will belong to group 2 of the periodic table.

(a) No, the oxidation state of Al is +3 and the covalency is 6. 

(b) Electron gain enthalpy generally becomes more negative across a period as we more from left to right. Within a group, electron gain enthalpy becomes less negative down a group. However, adding an electron to the 2p-orbital leads to more repulsion than adding an electron to the larger 3p-orbital. Hence, the element with most negative electron gain enthalpy is CI and the one with the least negative electron gain enthalpy is P 

(c) (i) Si is a group 14 element with a valence of 4; Br belongs to the halogen family with a valence of 1. Therefore, the formula of the compound formed would be SiBr_4. 

(ii) Al belongs to group 13 with a valence of 3, S belong to group 16 elements with valence of 2. Therefore, the formula of the compound formed would be Al₂S₃.

(i) A < C < B < D

(a) No, the oxidation state of Al is +3 and the covalency is 6.

(b) Electron gain enthalpy generally becomes more negative across a period as we more from left to right. Within a group, electron gain enthalpy becomes less negative down a group. However, adding an electron to the 2p-orbital leads to more repulsion than adding an electron to the larger 3p-orbital. Hence, the element with most negative electron gain enthalpy is CI and the one with the least negative electron gain enthalpy is P

(c) (i) Si is a group 14 element with a valence of 4; Br belongs to the halogen family with a valence of 1. Therefore, the formula of the compound formed would be SiBr₄.

(ii) Al belongs to group 13 with a valence of 3, S belong to group 16 elements with valence of 2. Therefore, the formula of the compound formed would be Al₂S₃.

(ii) P
(iii) S

There are 4 covalency of Al in (AICl₄]^-.

Second IE is always more than first IE because positive ion (cation) has more effective nuclear charge which holds the remaining electron more firmly and therefore, a large amount of energy is required to remove the electron from it as compared to a neutral atom.

The radius of Na⁺ is less than Na atom because Na⁺ is formed by losing one energy shell. 

Na – 1s² 2s² 2p⁶ 3s¹ 

Na⁺– 1s²2s² 2p⁶

The answer is (c) Ovaries of woman

• Well developed mammary glands.
• The high pitch of voice.

• Spermatogenesis needs a temperature of 34 to 35°C. 
• During winters, the outside temperature is low. 
• Hence, the scrotal sacs shrink to come closure to the body to get more heat.

The answer is Endometrium.

The answer is  Aldosterone.

The answer is Secretion of two hormones-Progesterone & Relaxin

Girls 

• During puberty your ovaries get bigger and your body will start to produce two hormones - oestrogen and progesterone. 
• Oestrogen causes your breast to grow and helps your vagina, uterus and fallopian tubes to develop. 
• It also makes you grow taller and also changes the way fat is stored on your body making your waist, hips and buttocks more obvious. 
• After puberty, oestrogen and progesterone control your menstrual cycle or period. 

Boys

• For young men, the hormone testosterone is the hormone that starts development from boy to man. 
• Testosterone is the major male sex hormone and it is produced in the testes.
• Testosterone levels rise significantly during puberty. 
• When levels are high enough, testosterone starts the production of sperm, causes the chest and shoulders to broaden and causes facial hair to grow.

• Male – Testes 
• Female – Ovaries

• They are special cells which are found inside the seminiferous tubeless of testes. 
• They provide support & nutrition to the sperms.

1. BKU conducted rallies, demonstrations, and Jail Bharo agitations.

2. These protests involved thousands so over lakhs farmers from western UP’s adjoining regions.

3. BKU operated as a pressure group in politics with its strength of sheer members.

Mercury and Venus are two planets which show phases like moon because they lie inside the orbit of Earth.

A complete set of units, both fundamental and derived for all kinds of physical quantities is called system of units.

True.

[Note: Choice of unit depends upon its suitability for measuring the magnitude of a physical quantity under consideration. Hence, we choose different scales for same physical quantity.]

1. Initial speed is at origin i.e. 0 m/s. 

2. Maximum speed attained by car, v_max = speed from A to B = 20 m/s. 

3. The part of the graph which shows zero acceleration is between t = 3 s and t = 6 s i.e., AB. This is because, during AB there is no change in velocity. 

4. The graph shows constant retardation from t = 6 s to t = 8 s i.e., BC. 

5. Distance travelled by car in first 6 s

= Area of OABDO 

= A(△OAE) + A(rect. ABDE)

= 1/2 × 3 × 20 + 3 × 20

= 30 + 60

∴ Distance travelled by car in first 6 s = 90 m

System of units are classified mainly into four types:

1. C.G.S. system:

It stands for Centimetre-Gram-Second system. In this system, length, mass and time are measured in centimetre, gram and second respectively.

2. M.K.S. system:

It stands for Metre-Kilogram-Second system. In this system, length, mass and time are measured in metre, kilogram and second respectively.

3. F.P.S. system:

It stands for Foot-Pound-Second system. In this system, length, mass and time are measured in foot, pound and second respectively.

4. S.I. system:

It stands for System International. This system has replaced all other systems mentioned above. It has been internationally accepted and is being used all over world. As the SI units use decimal system, conversion within the system is very simple and convenient.

S.I. system : It is known as International system of units. There are seven fundamental quantities in this system. 

These quantities and their units are given in the following table.

Besides the above seven fundamental units two supplementary units are also defined - Radian (rad) for plane angle and Steradian (sr) for solid angle.

Types :

(1) CGS system, 

(2) MKS system, 

(3) FPS system. 

(4) S.I. system 

By calculating range of the values of data on x – axis.