100525 + Interview Questions in GENERAL QA IN GENERAL AWARENESS

1.	State the Acidity or Hydroxity of a Base.
Answer» It may be defined as the number of OH^– ions furnished by a molecule of a base. A base can be, (i) Mono acidic or Monohydroxic like NaOH, NH₄OH, AgOH etc. (ii) Diacidic or dihydroxic like Ba(OH)₂, Mg(OH)₂, Ca(OH)₂, Sr(OH)₂ etc. (iii) Triacidic or trihydroxic like Fe(OH)₃, Al(OH)₃ etc.

1.

State the Acidity or Hydroxity of a Base.

Answer»

It may be defined as the number of OH^– ions furnished by a molecule of a base. A base can be,

(i) Mono acidic or Monohydroxic like NaOH, NH₄OH, AgOH etc.

(ii) Diacidic or dihydroxic like Ba(OH)₂, Mg(OH)₂, Ca(OH)₂, Sr(OH)₂ etc.

(iii) Triacidic or trihydroxic like Fe(OH)₃, Al(OH)₃ etc.

2.	Amongst the various ores of a metal (M) (sulphide, carbonates, oxides, hydrated or hydroxides) two ores [X] and [Y] show the following reactivity. (i)[X] on calcination gives a black solid (S), carbon dioxide and water. (ii)[X] Dissolved in dilute HCl, on reaction with Kl gives a white precipitate (P) and iodine. (iii)[Y] on roasting gives metal (M) and a gas `(G_(1))` which turns acidified `K_2Cr_2O_7` solution green. (iv)[Y] on reaction with dil.HCl gives a white precipitate (Q) and another gas `(G_2)` which turns lead acetate solution black, and also reacts with gas `(G_1)` to precipitate colloidal sulphur in presence of moisture. Reaction involved: (i)`CuCO_3. Cu(OH)_2oversetDeltatoCuOdarr("black")+CO_2+H_2O` `CuCO_3.Cu(OH)_2+4HCl to2CuCl_2+3H_2O+CO_2` (ii)`2Cu^(2+)+4I^(-)toCu_2l^2 darr (P)("white")+l_2uarr` (iii)`2Cu_2S+3O_2to2Cu_2O+2SO_2(G_1)` `Cu_2S+2Cu_2Oto6Cu+SO_2` (iv)`Cu_2S+2HCl to 2CuCldarr(Q)("white")+H_2S(G_2)` `Pb^(2+)+H_2StoPbSdarr("black")+2H^(+)` (v)`SO_2(G_1)+2H_2S(G_2)overset("moisture")to3Sdarr+2H_2O` The white precipitate (P) is of :A. `Cu_2I_2`B. `Cu I_2`C. `K_2[Cu l_4]`D. None
Answer» Correct Answer - A `CuCO_3+2HCl to CuCl_2+CO_2 +H_2O , CuCl_2 + 2KltoCu l_2 + 2KCl , 2Cu l_2 to Cu_2l_2 darr (P) +I_2`

Discussion

3.	Amongst the various ores of a metal (M) (sulphide, carbonates, oxides, hydrated or hydroxides) two ores [X] and [Y] show the following reactivity. (i)[X] on calcination gives a black solid (S), carbon dioxide and water. (ii)[X] Dissolved in dilute HCl, on reaction with Kl gives a white precipitate (P) and iodine. (iii)[Y] on roasting gives metal (M) and a gas `(G_(1))` which turns acidified `K_2Cr_2O_7` solution green. (iv)[Y] on reaction with dil.HCl gives a white precipitate (Q) and another gas `(G_2)` which turns lead acetate solution black, and also reacts with gas `(G_1)` to precipitate colloidal sulphur in presence of moisture. Reaction involved: (i)`CuCO_3. Cu(OH)_2oversetDeltatoCuOdarr("black")+CO_2+H_2O` `CuCO_3.Cu(OH)_2+4HCl to2CuCl_2+3H_2O+CO_2` (ii)`2Cu^(2+)+4I^(-)toCu_2l^2 darr (P)("white")+l_2uarr` (iii)`2Cu_2S+3O_2to2Cu_2O+2SO_2(G_1)` `Cu_2S+2Cu_2Oto6Cu+SO_2` (iv)`Cu_2S+2HCl to2CuCldarr(Q)("white")+H_2S(G_2)` `Pb^(2+)+H_2StoPbSdarr("black")+2H^(+)` (v)`SO_2(G_1)+2H_2S(G_2)overset("moisture")to3Sdarr+2H_2O` Which of the following statements is correct about [Y] ?A. [Y] is converted to metal (M) by self reductionB. Carbonate extract of [Y] gives yellow precipitate with suspension of `CdCO_3`C. [Y] is chalcocites or chalcopyritesD. All of these
Answer» Correct Answer - D It is sulphide ore (`Cu_2S` or `CuFeS_2`) & is called as chalcopyrites or chalcocities , `S^(2-)` gives yellow precipitate of CdS with `CdCO_3`

Discussion

4.	Amongst the various ores of a metal (M) (sulphide, carbonates, oxides, hydrated or hydroxides) two ores [X] and [Y] show the following reactivity. (i)[X] on calcination gives a black solid (S), carbon dioxide and water. (ii)[X] Dissolved in dilute HCl, on reaction with Kl gives a white precipitate (P) and iodine. (iii)[Y] on roasting gives metal (M) and a gas `(G_(1))` which turns acidified `K_2Cr_2O_7` solution green. (iv)[Y] on reaction with dil.HCl gives a white precipitate (Q) and another gas `(G_2)` which turns lead acetate solution black, and also reacts with gas `(G_1)` to precipitate colloidal sulphur in presence of moisture. Reaction involved: (i)`CuCO_3. Cu(OH)_2oversetDeltatoCuOdarr("black")+CO_2+H_2O` `CuCO_3.Cu(OH)_2+4HCl to2CuCl_2+3H_2O+CO_2` (ii)`2Cu^(2+)+4I^(-)toCu_2l^2 darr (P)("white")+l_2uarr` (iii)`2Cu_2S+3O_2to2Cu_2O+2SO_2(G_1)` `Cu_2S+2Cu_2O to6Cu+SO_2` (iv)`Cu_2S+2HCl to2CuCldarr(Q)("white")+H_2S(G_2)` `Pb^(2+)+H_2StoPbSdarr("black")+2H^(+)` (v)`SO_2(G_1)+2H_2S(G_2)overset("moisture")to3Sdarr+2H_2O` The gas `(G_1)` acts asA. Oxidising agentB. Reducing agentC. Oxidising and reducing agentD. Fluxing agent
Answer» Correct Answer - C `G_1=SO_2`, sulphur can increases & decreases its oxidation state.

Discussion

5.	Amongst the various ores of a metal (M) (sulphide, carbonates, oxides, hydrated or hydroxides) two ores [X] and [Y] show the following reactivity. (i)[X] on calcination gives a black solid (S), carbon dioxide and water. (ii)[X] Dissolved in dilute HCl, on reaction with Kl gives a white precipitate (P) and iodine. (iii)[Y] on roasting gives metal (M) and a gas `(G_(1))` which turns acidified `K_2Cr_2O_7` solution green. (iv)[Y] on reaction with dil.HCl gives a white precipitate (Q) and another gas `(G_2)` which turns lead acetate solution black, and also reacts with gas `(G_1)` to precipitate colloidal sulphur in presence of moisture. Reaction involved: (i)`CuCO_3. Cu(OH)_2oversetDeltatoCuOdarr("black")+CO_2+H_2O` `CuCO_3.Cu(OH)_2+4HCl to2CuCl_2+3H_2O+CO_2` (ii)`2Cu^(2+)+4I^(-)toCu_2l^2 darr (P)("white")+l_2uarr` (iii)`2Cu_2S+3O_2to2Cu_2O+2SO_2(G_1)` `Cu_2S+2Cu_2O to 6Cu+SO_2` (iv)`Cu_2S+2HCl to 2CuCldarr(Q)("white")+H_2S(G_2)` `Pb^(2+)+H_2StoPbSdarr("black")+2H^(+)` (v)`SO_2(G_1)+2H_2S(G_2)overset("moisture")to3Sdarr+2H_2O` The metal ores [X] and [Y] are respectively :A. Carbonate and sulphide oresB. Sulphide and carbonate oresC. Carbonate and hydroxide oresD. Carbonate and oxide ores
Answer» Correct Answer - A `[X]=CuCO_3 Cu(OH)_2 or 2CuCO_3. Cu(OH)_2 , [Y]=Cu_2S or CuFeS_2`

Discussion

6.	Which is incorrect:-A. `{:("Mixture","Separated by"),((1)Na_(2)S&CuS,H_(2)O):}`B. `{:("Mixture","Separated by"),((2)PbS & ZnS, NaCN):}`C. `{:("Mixture","Separated by"),((3)Fe_(2)O_(3)","Al_(2)O_(3),HCl):}`D. `{:("Mixture","Separated by"),((4)Al_(2)O_(3)","MgO,NaOH):}`
Answer» Correct Answer - C

Discussion

7.	______ are the only birds that can fly backwards.1. Common cranes2. Mallards3. Whooper swans4. Hummingbirds
Answer» Correct Answer - Option 4 : Hummingbirds The Correct Answer is Hummingbirds. Hummingbirds are the only birds that can fly backward. These Birds are the world’s smallest migrating birds. The design of these bird wings differs from most other types of birds. They have a unique ball and socket joint at the shoulder that allows the bird to rotate its wings 180 degrees in all directions. The shape of these bird wings is long, narrow, and tapered, which allows them to move more rapidly and easily through the air. Additionally, their shoulder and elbow joints of the wing are very close to their tiny bodies, allowing their wings to tilt and pivot. These characteristics allow these bird to change flight directions in such a way that other birds cannot.

7.

______ are the only birds that can fly backwards.1. Common cranes2. Mallards3. Whooper swans4. Hummingbirds

Answer» Correct Answer - Option 4 : Hummingbirds

The Correct Answer is Hummingbirds.

Hummingbirds are the only birds that can fly backward.
These Birds are the world’s smallest migrating birds.
The design of these bird wings differs from most other types of birds.
They have a unique ball and socket joint at the shoulder that allows the bird to rotate its wings 180 degrees in all directions.
The shape of these bird wings is long, narrow, and tapered, which allows them to move more rapidly and easily through the air. Additionally, their shoulder and elbow joints of the wing are very close to their tiny bodies, allowing their wings to tilt and pivot.
These characteristics allow these bird to change flight directions in such a way that other birds cannot.

Discussion

8.	______ is a long thick orange vegetable. A) tomato B) cucumber C) onion D) carrot
Answer» Correct option is D) carrot

Discussion

9.	An inorganic salt (A) is decomposed at about 523K to give products (B) and (C). Compound (C) is a liquid at room temperature and is neutral to litmus paper while compound (B) is used in dental surgery for anesthesia purpose. Compounds (A),(B),(C) wll be identified as-A. `NH_(4)NO_(3),N_(2)O,H_(2)O`B. `NH_(4)NO_(2),N_(2),H_(2)O`C. `CaCO_(3),CaO,H_(2)O`D. NH_(4)Cl, NH_(3),HCl`
Answer» Correct Answer - A

Discussion

10.	4NH3 (g) +5O2(g) =4NO(g)+6H2O(g)
Answer» Please refers to the below link http://bit.ly/2GBmCna

Discussion

11.	Sodium hydroxide solution is treated with Acidic acid to form sodium acetate and water
Answer» Sodium hydroxide solution is treated with acetic acid to form sodium acetate and water. NaOH + CH₃COOH → CH₃COONa + H₂O

11.

Sodium hydroxide solution is treated with Acidic acid to form sodium acetate and water

Answer»

Sodium hydroxide solution is treated with acetic acid to form sodium acetate and water.

NaOH + CH₃COOH → CH₃COONa + H₂O

Discussion

12.	4NH3+5O2=4no+6H2O
Answer» The reducing agent-- NH₃

Discussion

13.	Aluminum is exteracted from alumine `AI_(2)O_(3)` by electrolysis of a molten mixture of :A. `AI_(2)O_(3) +HF + NaIF_(4)`B. `AI_(2)O_(3) + CaF_(2) + NaAIF_(4)`C. `AI_(2)O_(3) + Na_(3)AIF_(6)+ CaF_(2)`D. `AI_(2)O_(3) +KF + Na_(3)Al_(4)^(2)`
Answer» Correct Answer - c Electrolysis of pure alumine faces to difficulties : (i) pure `AI_(2)O_(3))` is a bed conductor of electricity , (ii) fusion temperature of pure alumina is about `2000^(@)C` and at this temperature (when fused mass is electrolyzed) the metal found vaperizes as the boiling point of `AL` is `1800 ^(@)C` .The above difficulties are overcomed (hall- Heroult process) by using a mixture `AI_(2)O_(3))` cryolite`(Na_(3)AIF_(6))` and flursoar `(CaF_(2))` in the ratio of `20 : 40: 20` .The fusion temperature mixture is `900^(@)C` and it is good conductor of electricity .

Discussion

14.	In which case the energy change is minimum :A. `Cl rarr Cl^(-)`B. `P rarrP^(-)`C. `N rarrN^(-)`D. `C rarr C^(-)`
Answer» Correct Answer - C `(1)CgtPgtN` `3^(rd)` period `EA gt 2^(nd)` period EA `N rarr 2p^(3)` electronic configration.

Discussion

15.	A drop of a liquid sample was put on the pH paper. It was observed that the colour of the pH paper turned blue. The liquid sample isA. lemon chainB. sodium bicarbonate solutionC. distilled waterD. hydrochloric acid
Answer» Correct Answer - B

Discussion

16.	Find the number of moles of electrons present in the biggest unit of charge
Answer» We know that the biggest unit of charge is Faraday. 1 Faraday contains only 1 mole of electrons. Hence, no of moles of electrons present in the biggest unit of charge is 1.

Discussion

17.	0.5 mole of `SO_2` gas at `27^@C` is expanded in reversible adiabatic condition to make volume 8 times.Final temperature (in K) and work done by gas (in Cal) respectively are x and y.Report your answer as `y/x`. (Take ideal behaviour of gas, R=2 Cal/K mol and `2^(1.2)=2.3`)
Answer» Correct Answer - 3 `T_1V_1^(gamma-1)=T_2V_2^(gamma-1)implies 300xxV^(1//3)=T_2(8V)^(1//3)implies T_2=150 K` `W=nC_v(T_2-T_1)=0.5xx3 R(150-300)=0.5xx3xx2(-150)=-450`cal

Discussion

18.	Give advantages of long form of periodic table.
Answer» a. It relates position of periodic table with electronic configuration. b. It reduces study of `114` elements into `18` groups and `7` periods. c. It helps in discovery of new elements.

Discussion

19.	Which one of the following alkaline earth metal sulphates has its hydration enthalpy greater than its lattice enthalpy?A. `CaSO_(4)`B. `BeSO_(4)`C. `BaSO_(4)`D. `SrSO_(4)`
Answer» Correct Answer - B `BaBO_(4)` is least soluble. `BeSO_(4)` is most soluble.

Discussion

20.	Give five characteristics of `p`-block elements.
Answer» a.They consist of solids, liquids and gases. They consist of metals, non-metals and metalloids. They show variable valency d. They form both ionic and covalent compounds. e. Most of them are good oxidising agents.

Discussion

21.	a. Among `Cu^(o+)`,`Cu^(2+)` and `Cu` which is the largest in size and why? b. Which element in periodic table has the highest `IE` (ionisation energy)? c. Which element, `Mg` or `Al`, is more metallic and why?
Answer» a. `Cu` is largest due to less effective nuclear charge. It has `29` electrons , `29` protons, `Cu^(+)` has `28` electrons and `29`protons, `Cu^(2+)` has `27` electrons and `29` protons . b. He has the highest ionisation energy. c. `Mg` is more metallic due to lower ionisation energy.

Discussion

22.	Which of the following orders is correct for the size ? (1)`Mg^(2+)ltNa^(+)ltF^(-)ltAl` (2)`Al^(3+)ltMg^(2+)ltLi^(+)ltK^(+)` (3)`Fe^(4+)ltFe^(3+)ltFe^(2+)ltFe` (4)MggtAlgtSigtPA. (1),(2)&(3)B. (2),(3) & (4)C. (1),(3) & (5)D. (1),(2),(3) & (4)
Answer» Correct Answer - D (1)`Mg^(2+),Na^(+) and F^(-)` are isoelectronic and thus follows the order `._12 Mg^(2+) lt ._(11)Na^(+) lt ._9F^(-)` All belongs to third period and has no charge so it is largest. `Na^(+)=102` pm , `Mg^(2+)` =72 pm, Al=143 pm, `F^-`=133 pm. (2)`K^+` has more number of shells than `Mg^(2+)` and `Al^(3+)` .`Al^(3-)` and `Mg^(2+)` are isoelectronic but `Al^(3+)` has higher nuclear charge so `Al^(3+) lt Mg^(2+) . Mg^(2+)` and `Li^(+)` has diagonal relationship.But due to +2 charge to +2 charge in `Mg^(2+)` , the `Mg^(2+)` is smaller than `Li^(+)`.Hence `Al^(3+)` is the smallest one. `K^(+)=1.38Å, Li^(2+)=0.76 Å, Mg^(2+)=0.72 Å, Al^(3+)=0.535 Å` (3)As the number of electrons are lost , the attraction between valence shell electrons and nucleus increases As a consequence of this the electrons are pulled closer to the nucleus leading to the contraction in size of ions. (4)Across the period the nuclear charge increases and thus the size of atoms decreases, Mg=160 pm, Al=143 pm , Si=118 , P=110 pm

Discussion

23.	Match the values of ionization energy and electron gain enthalpy listed in column I with characteristic(s) of elements listed in column II. `{:("Column-I","Column-II"),((A)"2372 5251 +48",(p)"Element which acts as a strong reducing agent"),((B)"419 3051 -48",(q)"Element which exists as a monoatomic molecule"),((C )"1681 3374 -333",(r)"Least reactive non-metal"),((D)"1008 1846 -295",(s)"Element which acts as a strong oxidising agent"),(,(t)"Element which oxides is a stronger basic in nature"):}`
Answer» Correct Answer - A`to`q ; B`to`p,t ;C`to`s ; D`to`r (A)Inert gas exist as monoatomic molecule. They have highest `IE_1` and `IE_2` and positive electron gain enthalpies. (B)Alkali metal -`IE_1` is low because of bigger size of atom and `IE_2` is high due to noble gas configuration . As it has low `IE_1` it can lose one electron easily and thus more electropositive .So it acts as strong reducing agents and their oxides are basic in nature.They have low negative value of `DeltaH_(eg)` because of large size. (C )`IE_1 and IE_2` both high and negative value of electron gain enthalpy is very high because of high nuclear charge and small size of atoms, so it has a greater tendency to accept an additional electron.So it (F) act as a strong oxidising agent. (D)As it has less negative value for `DeltaH_(eg)` than (C ) thus it will be least reactive non-metal (I)

Discussion

24.	A narrow beam of white light goes through a slab having parallel faces(a) the light never splits in different colours(b) the emergent beam is white(c) the light inside the slab is split into different colours(d) the light inside the slab is white
Answer» (b,c) If faces of prism on which light is incident & from which it emerge are parallel, then angle of prism will be zero & so deviation will also be zero i.e., the prism will act as a transparent prism

Discussion

25.	Identify the wrong sign convention(a) The magnification for virtual image formed by a convex lens is positive(b) The magnification for real image formed by a convex lens is negative(c) The height measured normal to the principal axis upwards is positive(d) The magnification for virtual image formed by a concave lens is negative
Answer» (d) The magnification for vertual image formed by concave lens is positive.

Discussion

26.	The speed of light in an isotropic medium depends on(a) the nature of the source(b) its wavelength(c) its direction of propagation(d) its intensity
Answer» (b) In an isotropic medium, speed of light depends on its wavelength.

Discussion

27.	Circinate vernation is found inA. Moss/Funaria/RicciaB. Fern/Dryopteris/PterisC. PinusD. Both A and B
Answer» Correct Answer - B Circinate vernation is found in fern.

Discussion

28.	The apparent flattening of the sun at sunset and sunrise is due to(a) refraction(b) diffraction(c) total internal reflection(d) interference
Answer» (a) The apparent flattening (oval shape) of the sun at sunset and sunrise is due to refraction

Discussion

29.	In ferns, the term frond is used forA. RootB. StemC. LeavesD. Capsule
Answer» Correct Answer - C In ferns, the term frond is used for leaves.

Discussion

30.	A parallel beam of light is incident on a converging lens parallel to its principal axis. As one moves away from the lens on the other side on its principal axis, the intensity of light(a) remains constant(b) continuously increases(c) continuously decreases(d) first increases then decreases
Answer» (a) remains constant

Discussion

31.	The rays of different colours fail to converge at a point after going through a converging lens. This defect is called(a) spherical aberration(b) distortion(c) coma(d) chromatic aberration
Answer» (d) chromatic aberration. EXPLANATION: Since the refractive index of a medium is different for different colors. Hence the rays of different colors fail to converge at a point. Since this aberration is related to colored rays it is called a chromatic aberration because chrome is a Greek word for color.

31.

The rays of different colours fail to converge at a point after going through a converging lens. This defect is called(a) spherical aberration(b) distortion(c) coma(d) chromatic aberration

Answer»

(d) chromatic aberration.

EXPLANATION:

Since the refractive index of a medium is different for different colors. Hence the rays of different colors fail to converge at a point. Since this aberration is related to colored rays it is called a chromatic aberration because chrome is a Greek word for color.

Discussion

32.	Sunlight reaches to us in composite form and not in its constituent colours becauseI. vacuum is non–dispersive.II. speed of all colours is same in vacuum.III. light behaves like a particle in vacuum.IV. light travels in a straght line in vacuum.(a) I and II (b) II and III (c) III and IV(d) I and IV
Answer» (a) The variation of refractive index with wavelength may be more pronounced in some media than the other. In vacuum, of course, the speed of light is independent of wavelength. Thus, vacuum (or air approximately) is a non dispersive medium in which all colours travel with the same speed. This also follows from the fact that sunlight reaches us in the form of white light and not as its components. On the other hand, glass is a dispersive medium

Discussion

33.	The focal length of a normal eye-lens is about(a) 1 mm (b) 2 cm(c) 25 cm (d) 1 m
Answer» The focal length of a normal eye-lens is (b) 2 cm

33.

The focal length of a normal eye-lens is about(a) 1 mm (b) 2 cm(c) 25 cm (d) 1 m

Answer»

The focal length of a normal eye-lens is (b) 2 cm

Discussion

34.	The difference between reflection and total internal reflection is that(a) the laws of reflection hold true for reflection but not for total internal reflection.(b) total internal reflection can take place only when light travels from a rarer medium to a denser medium while reflection can take place vice-versa also.(c) reflection can take place when light travels from a rarer medium to denser medium and vice-versa but total internal reflection can take place only when it travels from an optically denser to an optically rarer medium.(d) reflection is a natural phenomena while total internal reflection is man-made
Answer» (c) For total internal reflection light ray must travel from optically denser to an optically rarer medium.

Discussion

35.	Astigmatism is corrected using(a) cylindrical lens (b) plano-convex lens(c) plano-concave lens (d) convex lens
Answer» (a) Cylindrical lens is used to rectify eye defect astigmatism

Discussion

36.	Total internal reflection can take place only if(a) light goes from optically rarer medium (smaller refractive index) to optically denser medium(b) light goes from optically denser medium to rarer medium(c) the refractive indices of the two media are close to different(d) the refractive indices of the two media are widely different
Answer» (b) According to Snell’s Law, sin i/ sin r =μ ₂/μ ₁ = where r = 90º for particular incidence angle called critical angle. When the incidence angle is equal to or greater than i_c , then total internal reflection occurs. It takes place when ray of light travels from optically denser medium (μ₁> μ₂ ) to optically rarer medium.

Discussion

37.	Which light rays undergoes two internal reflection inside a raindrop, which of the rainbow is formed?(a) Primary rainbow (b) Secondary rainbow(c) Both (a) and (b) (d) Can’t say
Answer» (b) Secondary rainbow is formed by rays undergoing interanal reflection twice inside the drop

Discussion

38.	Identify the mismatch in the following(a) Myopia - Concave lens(b) For rear view - Concave mirror(c) Hypermetropia - Convex lens(d) Astigmatism - Cylindrical lens
Answer» (b) For rear view, Convex mirror is used in vehicle

Discussion

39.	Which of the following statements about laws of reflection is/are correct?I. The incident ray, the reflected ray and the normal all lie in the same plane.II. Angle of incidence is equal to the angle of reflection.III. After reflection, velocity, wavelength and frequency of light remains same but intensity decreases.(a) I only (b) II only(c) I and II (d) I, II and III
Answer» statements about laws of reflection are correct (d) I, II and III

Discussion

40.	Which of the following is/are correct relations?
Answer» . (a) If n₂₁ is the refractive index of medium 2 with respect to medium 1 and n₁₂the refractive index of medium 1 with respect to medium 2, then it should be clear that n₁₂=1/n₂₁ It also follows that if n₃₂is the refractive index of medium 3 with respect to medium 2, then n₃₂ = n₃₁ × n_12, where n₃₁ is the refractive index of medium III with respect to medium I.

Discussion

41.	Directions : Each of these questions contains two statements, Assertion and Reason. Each of these questions also has four alternative choices, only one of which is the correct answer. You have to select one of the codes (a), (b), (c) and (d) given below.(a) Assertion is correct, reason is correct; reason is a correct explanation for assertion.(b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion(c) Assertion is correct, reason is incorrect(d) Assertion is incorrect, reason is correctAssertion : Two convex lenses joined together cannot produce an achromatic combination.Reason : The condition for achromatism is ω1/f1 +ω2/f2 =0 where symbols have their usual meaning
Answer» (a) Assertion is correct, reason is correct; reason is a correct explanation for assertion.

Discussion

42.	Directions : Each of these questions contains two statements, Assertion and Reason. Each of these questions also has four alternative choices, only one of which is the correct answer. You have to select one of the codes (a), (b), (c) and (d) given below.(a) Assertion is correct, reason is correct; reason is a correct explanation for assertion.(b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion(c) Assertion is correct, reason is incorrect(d) Assertion is incorrect, reason is correct.Assertion : Critical angle is minimum for violet colour.Reason : Because critical angle θc=sin-1(1/μ) and μ∝1/λ
Answer» (a) Assertion is correct, reason is correct; reason is a correct explanation for assertion.

Discussion

43.	Which of the following is correct for the beam which enters the medium?(a) Travel as a cylindrical beam(b) Diverge(c) Converge(d) Diverge near the axis and converge near the periphery
Answer» (c) Since the refractive index is less at beam boundary, the ray at the edges of the beam move faster compared to the axis of beam. Hence the beam converges

Discussion

44.	If D is the deviation of a normally falling light beam on a thin prism of angle A and δ is the dispersive power of the same prism then(a) D is independent of A.(b) D is independent of refractive Index.(c) δ is independent of refractive index.(d) δ is independent of A.
Answer» (d) δ is independent of A.

Discussion

45.	The dispersive power of material of a lens of focal length 20 cm is 0.08. What is the longitudinal chromatic aberration of the lens ?(a) 0.08 cm (b) 0.08/20 cm (c) 1.6 cm (d) 0.16 cm
Answer» (c) Longitudinal chromatic aberration = ω_f = 0.08 × 20 = 1.6 cm

Discussion

46.	Which of the following phenomena is used in optical fibres ?(a) Total internal reflection(b) Scattering(c) Diffraction(d) Refraction
Answer» (a) The basic principle of communication in fibre optics is based on the phenomenon of total internal reflection.

Discussion

47.	Which of the following is not due to total internal reflection?(a) Working of optical fibre(b) Difference between apparent and real depth of pond(c) Mirage on hot summer days(d) Brilliance of diamond
Answer» (b) Difference between apparent and real depth of a pond is due to the refraction of light, not due to the total internal reflection. Other three phenomena are due to the total internal reflection

Discussion

48.	The dispersive power of a prism depends on its(a) shape(b) size(c) angle of prism(d) refractive index of the monitorial of the prism
Answer» (d) refractive index of the monitorial of the prism

Discussion

49.	Assertion: Neopentane forms one mono substitutes compound Reason: Neopentane is an isomer of pentane.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If assertion is false but reason is true.
Answer» Correct Answer - B Neopentane is isomer of pentane and neopentane forms only one substitution product. Both assertion and reason are true but reason is not the correct explanation of assertion. Neopentane forms monosubstitued product due to presence of four identical methyl groups present on carbon atom.

Discussion

50.	Arrange the following in their nucleophilicity order. (I) `C_(6)H_(5)O^(Theta)` (II) `C_(6)H_(5)S^(Theta)` (III) `C_(6)H_(5) - overset(Theta)CH_(2)` (IV) `CH_(3)-overset(O)overset(\|\|)C-overset(Theta)CH_(2)`A. `II gt III gt IV gt I`B. `I gt IV gt II gt III`C. `II gt IV gt III gt I`D. `III gt IV gt I gt II`
Answer» Correct Answer - A Nucleophiclicity of `S^(-)` is more as it is weak base.

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

State the Acidity or Hydroxity of a Base.

Which is incorrect:-A. `{:("Mixture","Separated by"),((1)Na_(2)S&CuS,H_(2)O):}`B. `{:("Mixture","Separated by"),((2)PbS & ZnS, NaCN):}`C. `{:("Mixture","Separated by"),((3)Fe_(2)O_(3)","Al_(2)O_(3),HCl):}`D. `{:("Mixture","Separated by"),((4)Al_(2)O_(3)","MgO,NaOH):}`

______ are the only birds that can fly backwards.1. Common cranes2. Mallards3. Whooper swans4. Hummingbirds

______ is a long thick orange vegetable. A) tomato B) cucumber C) onion D) carrot

4NH3 (g) +5O2(g) =4NO(g)+6H2O(g)

Sodium hydroxide solution is treated with Acidic acid to form sodium acetate and water

4NH3+5O2=4no+6H2O

Aluminum is exteracted from alumine `AI_(2)O_(3)` by electrolysis of a molten mixture of :A. `AI_(2)O_(3) +HF + NaIF_(4)`B. `AI_(2)O_(3) + CaF_(2) + NaAIF_(4)`C. `AI_(2)O_(3) + Na_(3)AIF_(6)+ CaF_(2)`D. `AI_(2)O_(3) +KF + Na_(3)Al_(4)^(2)`

In which case the energy change is minimum :A. `Cl rarr Cl^(-)`B. `P rarrP^(-)`C. `N rarrN^(-)`D. `C rarr C^(-)`

A drop of a liquid sample was put on the pH paper. It was observed that the colour of the pH paper turned blue. The liquid sample isA. lemon chainB. sodium bicarbonate solutionC. distilled waterD. hydrochloric acid

Find the number of moles of electrons present in the biggest unit of charge

0.5 mole of `SO_2` gas at `27^@C` is expanded in reversible adiabatic condition to make volume 8 times.Final temperature (in K) and work done by gas (in Cal) respectively are x and y.Report your answer as `y/x`. (Take ideal behaviour of gas, R=2 Cal/K mol and `2^(1.2)=2.3`)

Give advantages of long form of periodic table.

Which one of the following alkaline earth metal sulphates has its hydration enthalpy greater than its lattice enthalpy?A. `CaSO_(4)`B. `BeSO_(4)`C. `BaSO_(4)`D. `SrSO_(4)`

Give five characteristics of `p`-block elements.

a. Among `Cu^(o+)`,`Cu^(2+)` and `Cu` which is the largest in size and why? b. Which element in periodic table has the highest `IE` (ionisation energy)? c. Which element, `Mg` or `Al`, is more metallic and why?

Which of the following orders is correct for the size ? (1)`Mg^(2+)ltNa^(+)ltF^(-)ltAl` (2)`Al^(3+)ltMg^(2+)ltLi^(+)ltK^(+)` (3)`Fe^(4+)ltFe^(3+)ltFe^(2+)ltFe` (4)MggtAlgtSigtPA. (1),(2)&(3)B. (2),(3) & (4)C. (1),(3) & (5)D. (1),(2),(3) & (4)

A narrow beam of white light goes through a slab having parallel faces(a) the light never splits in different colours(b) the emergent beam is white(c) the light inside the slab is split into different colours(d) the light inside the slab is white

The speed of light in an isotropic medium depends on(a) the nature of the source(b) its wavelength(c) its direction of propagation(d) its intensity

Circinate vernation is found inA. Moss/Funaria/RicciaB. Fern/Dryopteris/PterisC. PinusD. Both A and B

The apparent flattening of the sun at sunset and sunrise is due to(a) refraction(b) diffraction(c) total internal reflection(d) interference

In ferns, the term frond is used forA. RootB. StemC. LeavesD. Capsule

A parallel beam of light is incident on a converging lens parallel to its principal axis. As one moves away from the lens on the other side on its principal axis, the intensity of light(a) remains constant(b) continuously increases(c) continuously decreases(d) first increases then decreases

The rays of different colours fail to converge at a point after going through a converging lens. This defect is called(a) spherical aberration(b) distortion(c) coma(d) chromatic aberration

The focal length of a normal eye-lens is about(a) 1 mm (b) 2 cm(c) 25 cm (d) 1 m

Astigmatism is corrected using(a) cylindrical lens (b) plano-convex lens(c) plano-concave lens (d) convex lens

Which light rays undergoes two internal reflection inside a raindrop, which of the rainbow is formed?(a) Primary rainbow (b) Secondary rainbow(c) Both (a) and (b) (d) Can’t say

Identify the mismatch in the following(a) Myopia - Concave lens(b) For rear view - Concave mirror(c) Hypermetropia - Convex lens(d) Astigmatism - Cylindrical lens

Which of the following is/are correct relations?

Which of the following is correct for the beam which enters the medium?(a) Travel as a cylindrical beam(b) Diverge(c) Converge(d) Diverge near the axis and converge near the periphery

If D is the deviation of a normally falling light beam on a thin prism of angle A and δ is the dispersive power of the same prism then(a) D is independent of A.(b) D is independent of refractive Index.(c) δ is independent of refractive index.(d) δ is independent of A.

The dispersive power of material of a lens of focal length 20 cm is 0.08. What is the longitudinal chromatic aberration of the lens ?(a) 0.08 cm (b) 0.08/20 cm (c) 1.6 cm (d) 0.16 cm

Which of the following phenomena is used in optical fibres ?(a) Total internal reflection(b) Scattering(c) Diffraction(d) Refraction

Which of the following is not due to total internal reflection?(a) Working of optical fibre(b) Difference between apparent and real depth of pond(c) Mirage on hot summer days(d) Brilliance of diamond

The dispersive power of a prism depends on its(a) shape(b) size(c) angle of prism(d) refractive index of the monitorial of the prism