100525 + Interview Questions in GENERAL QA IN GENERAL AWARENESS

1.	At a wedding, the bride usually wears a ___dress.
Answer» Correct answer is white

Discussion

2.	The system shown in the figure is in equilibrium. Masses `m_(1) & m_(2)` are 2kg and 8 kg respectively. The compression in right spring is 0.5 m. (Both spring have the same natural length) `[K_(1)=20 N//m, K_(2)=70 N//m]`. Choose the correct option(s) : A. elongation in left spring is 0.5mB. elongation in left spring is 0.25 mC. Tension is string is 45 ND. Just after left spring is cut `m_(1)`, has upward acceleration.
Answer» Correct Answer - A::B::C F = 8t `m(dv)/(dt) = 8t` `m underset(0)overset(v)int dv = 8 underset(0) overset(t) int t dt` `mv = 4t^(2)` or `m(dx)/(dt) = 4t^(2) implies dx = (4t^(2))/(m) dt = 2t^(2) dt` `W = intFdx = underset(0)overset(2)int (8t xx 2t^(2)) dt = 64J`

Discussion

3.	A box is failing freely. Inside the box, a particle is projected with some velocity v with respect to the box at an angle `theta` as shown in the figure. A. The path of the particle with respect to an observer sitting in the box will be a straight line.B. The acceleration of particle with respect to the box is zero.C. The path of the particle with respect to an observer sitting in the box will be a parabolaD. The acceleration of particle with respect to ground is g downward
Answer» Correct Answer - A::B::C Loss in KE = `(1)/(2) (m_(1)m_(2))/(m_(1)+m_(2))(V_("rel"))^(2)(1-e^(2))`

Discussion

4.	A uniform field is exists in the region directed away from the page. A charged particle, moving in the plane of the page follows a anticlockwise spiral of increasing radius as shown. True explanation is: A. the charge is positive and slowing downB. the charge is negative and slowing downC. the charge is positive and speeding upD. the charge is negative and speeding up
Answer» Correct Answer - A `R=(mv)/(qB)` : `vec(F) = q(vec(v)xxvec(B))`

Discussion

5.	A block of mass m is placed on a smooth block of mass `M = m` with the help of a spring as shown in the figure. A velocity `v_(0)` is given to upper block when spring is in natural length. Find maximum compression in the spring. A. `sqrt((m)/(2K)) V_(0)`B. `sqrt((m)/(K)) v_(0)`C. `sqrt((2m)/(K)) v_(0)`D. `2 sqrt((m)/(K)) v_(0)`
Answer» Correct Answer - A Compression will be maximum when relative velocity between blocks is zero. Means both have Sam velocity apply conservation of momentum `mv_(0) = (M + m) v` `rArr v = (m)/(M + m) v_(0)` Apply conservation of kinetic energy `(1)/(2) mv^(2) + (1)/(2) Mv^(2) + (1)/(2) kx^(2) = (1)/(2) mv_(0)^(2)` `rArr (m^(3)v_(0)^(2))/((M + m)^(2)) + (m^(2)Mv_(0)^(2))/((M + m)^(2)) + kx^(2) = mv_(0)^(2)` `rArr kx^(2) = (m^(3) + m^(2)M)/((M + m)^(2)) v_(0)^(2) = mv_(0)^(2)` `rArr kx^(2) = v_(0)^(2) [(m)/(p) - (m^(2) (M + m))/((M + m)^(2))]` `= v_(0)^(2) [(M_(m) + m^(2) - m^(2))/(M + m)] = (M_(m)v_(0)^(2))/(M + m)` `rArr x = sqrt((Mm)/(k(M + m))) v_(0)`

Discussion

6.	A uniform field is exists in the region directed away from the page. A charged particle, moving in the plane of the page follows a anticlockwise spiral of increasing radius as shown. True explanation is: A. charge is positive and slowing downB. charge is negative and slowing downC. charge is positive and speeding upD. charge is negative and speeding up
Answer» Correct Answer - D `R=(mV)/(qB) , R uarr , v uarr`

Discussion

7.	Water kept in a porcus pot evaporates through the walls of pot. Rate of evaporation is proportional to volume of water. When water is kept in the pot 75% water get evaporated in 16 hrs. A suction mechanism attached in the pot sucks water at the rate which is also proportional to volume of water in the pot. Without evaporations, half of the water kept in pot is sucked in 24 hr The pot is filled with 16 kg of water, with evaporation and suction acting simultaneously , what amount of water (in kg) will be left is pot after one day.
Answer» Correct Answer - `0001` Evaporations and reaction has rate similar to first order reaction rate hence `1/t_(1//2)=1/((t_(1//2))_(evoparation))+1/((t_(1//2))_(suction))Rightarrow1/(t_(1//2))=6`hrs `Hence water left =16/2^(4)=1kg`

Discussion

8.	The reaction `_(3)^(7)Li+_(1)^(1)H rightarrow _(4)^(7)Be + _(0)^(1)n` is endothermic. Assuming that Li nuclei is free and at rest. What is the minimum kinetic energy ( in keV) of incident proton so that this reaction occurs? Take Q value of this reaction as -1645 keV.
Answer» Correct Answer - `1880 ke V` Energy available `=1/2mu v_(rel)^(2)=Q` value `=1/2xx(7xx1)/(7+1)xxv_(rel)^(2)=Q` value `Rightarrow 1/2xxv_(rel)^(2)=Qxx8/7` `K_(i)=1645xx8/7=1880` ke V

Discussion

9.	In a sample initially there are equal number of atoms of two radioactive isotopes A and B. 3 days later the number of atoms of A is twice that of B. Half life of B is `1.5` days. What is half life of isotope A? (in days)
Answer» Correct Answer - `0003` `A B t=0 N_(0) N_(0)` `t_(0)=3 days 2N N` `2N=N_(0)(0.5)t_(0)//tau_(1)` `N=N_(0)(0.5) t_(0)//tau_(2)` `2=(0.5) t_(0)(1/tau_(1)-1/tau_(2))` `Rightarrow 0.5^(-1)=(0.5)(3/tau_(1)-2)` `Rightarrow -1=3/tau_(1)-2 :.tau_(1)=3` days

Discussion

10.	In a slow reaction, heat is being evolved at a rate about 10 m W in a liquid. If the heat were being generated by the decay `of ^(32)` P, a radioactive isotope of phosphorus that has half-life of 14 days and emits only beta-particles with a mean energy of 700KeV, estimate the number `of ^(32)` P atoms in the liquid. Express your answer in form of `Axx10^(15)` and fill A in OMR sheet. Round off A to nearest integer [Take:l n`2=0.7`]
Answer» Correct Answer - `0154` `P=700xx10^(3)xx1.6xx10^(-19)xx(dN)/(dt)=10xx10^(-3)` `(dN)/(dt)=10^(-2)/10^(-14)xx1/(7xx16)=10^(12)/11.2=lambda N_(0)` `lambda=(l n2)/(14xx86400) Rightarrow N_(0)=(14xx86400xx10^(12))/(11.2l n2)=154xx10^(15)`

Discussion

11.	A capstan is a rotating drum (cylinder) over which a rope or cord slides in order to increase the tension due to friction. If the difference in tension between the two ends of the rope is 500 N and the capstan has a diameter of 10 cm and rotates with angular velocity `10 rad//s`. Capstan is made of iron and has mass 5 kg, specific heat `1000 J//kg` K. At what rate does temperature rise? Assume that the temperature in the capstan is uniform and all the thermal energy generated flows into it. Express your answer as `xxx10^(-4)^(@)C` Fill up value of x.
Answer» Correct Answer - `0500` `P=tauomega=(500xx5xx10^(-2))xx10` `P=ms(dT)/(dt)` `(dT)/(dt)=500xx5xx10^(-2)xx10=5xx10^(-2)` `x xx10^(-4)=5xx10^(-2)=500`

Discussion

12.	Interference frings of yellow light of wavelength 6000 A are formed by Billet split lenses. The distance from source to lens is 24 cms. The focal length of lens is 15 cm The lens halves are separated by `0.06` mm. The distance of source to screen is 200 cms. Calculate the fringe width (in mm) Round off the answer to nearest integer.
Answer» Correct Answer - `5 mm` `u=-24` `v=(uf)/(u+f)` `v=(-24xx15)/(-24+15)=(124xx15)/8=40` `Rightarrow D=200-24-40=136` cm `(R_(1))/(-0.03)=v/u=40/(-24)` `R_(1)=40/24xx0.03=0.05` mm `Rightarrow d=0.05xx2+0.06=0.16xx10^(-3)`m `beta=(lamdaD)/d=(6000xx10^(-10)xx136xx10^(-2))/(0.16xx10^(-3))` `beta=51xx10^(-4)m=5.1` mm

Discussion

13.	In a modified YDSE the sources S of wavelength 5000 A oscillates about axis of setup according to the equation `y=0.5 sin(pi/6)t` where y is in millimeter and t in second. At what time ti will the intensity at P, a point exactly in front of slit `S_(1)` be maximum for the first time?
Answer» Correct Answer - `0001` The path difference at point P, `Deltax=(SS_(2)-SS_(1))+(S_(2)P-S_(1)P)` `=(dy)/(D_(1))+(d(d//2))/D_(2)` For constructive interference, `Deltax=(dy)/D_(1)+d^(2)/(2D_(2))=nlambda` `((10^(-3))(0.5sinpit)xx10^(-3))/1+(10^(-3))^(2)/(2xx2)=nlambda` `(0.5sin(pi/6)t)xx10^(-6)+0.25xx10^(-6)` `=(5000xx10^(-10)) n=0.5xx10^(-6)`n `sin(pi/6)t=(0.5n-0.25)/0.5` For the minimum value of t n=1 `sin(pi/6)t=1/2 Rightarrow (pi/6)t=pi/6 or t=1 sec`

Discussion

14.	The spatial distribution of the electric field due to charges `(A,B)` is shown in figure. Which of the following statements is correct? A. `A` is `+ve` and `B-ve` and `\|A\|gt\|B\|`B. `A` is `-ve` and `B+ve, \|A\|=\|B\|`C. Both are `+ve` but `AgtB`D. Both are `-ve` but `AgtB`
Answer» Correct Answer - a Electric lines of force usually start (i.e., diverge out) from positive charge and end(i.e., converge) on negative charge or extendes to infinity. Thus, `A` is positive charge and `B` is negative charge. Also density of lines at `A` is more than that at `B`, i.e., `\|A\|gt\|B\|`.

Discussion

15.	If the sum of two unit vectors is a unit vector, then magnitude of difference is-A. `sqrt(2)`B. `sqrt(3)`C. `(1)/sqrt(2)`D. `sqrt(5)`
Answer» Correct Answer - B `\|hatn_(2)+hatn_(2)\|=1` `sqrt(1^(2)+1^(2)+2 cos theta)=12+2 cos theta=1` `rArr costheta=(-1)/(2)rArrtheta=120^(@)` `\|hatn_(1)-hatn_(2)\|=sqrt(1^(2)+1^(2)-2xx1xxa cos 120^(@))=sqrt(3)`

Discussion

16.	Which of the following sets of concurrent force may be in equilibrium?A. `F_1= 3N, F_2= 5N, F_3= 1N`B. `F_1 = 3N, F_2 = 5N, F_3= 9N`C. `F_1 = 3N, F_2= 5N, F_3= 6N`D. `F_1= 3N, F_2= 5N, F_3= 15N`
Answer» Correct Answer - 3 `F_1 - F_2 le \|vecF_1 + vec F_2\| le F_1 + F_2 ` To produce zero resultant `F_3` must lie between `F_1 - F_2 le F_3 le F_1 + F_2`

Discussion

17.	What is the torque of the force `vecF=(2hati+3hatj+4hatk)N` acting at the point `vecr=(2hati+3hatj+4hatk)m` about the origin? (Note: Tortue, `vectau=vecrxxvecF`)
Answer» `"Torque" vectau=vecrxxvecF=\|{:(hati,hatj,hatk),(2,3,4),(2,3,4):}\|=hati(12-12)-hatj(8-8)+hatk\|6-6\|=0hati-0hati-0hatj+ohatk=vec0`

Discussion

18.	The magnitudes of vectors `vecA.vecB` and `vecC` are respectively 12,5 and 13 unira and `vecA+vecB=vecC`, then the angle between `vecA` and `vecB` is :
Answer» Correct Answer - C `vecA+vecB=vecC` as `vecA^(2)+B^(2)=C^(2)` thus angle between A and B is `90^(@)`

Discussion

19.	Potential energy of a particle of mass `m`, depends on distance `y` from line `AB` according to given relation `U = (K)/(sqrt(y^(2) + a^(2))`, where `K` is a positive constant. A particle of mass `m` is projected from `y = sqrt(3)` towards line `AB`. (perpendicular to it) then minimum velocity so that it connot return to its initial point is `sqrt((K)/(aNm))`, calculate `N`.
Answer» Correct Answer - 1 `U_(i) + k_(i) = U_(f) + k_(f)` `(K)/(2a) + (1)/(2)mV_(0)^(2) = (K)/(a)` `(mV_(0)^(2))/(2) = (K)/(2a) rArr v_(0) = sqrt((K)/(am))`

Discussion

20.	All the pulleys are ideal, string is massless then rate of work done by gravity at the given instant is `(-x xx 10^(2))W` then calculate `x` :
Answer» Correct Answer - 5 `v_(p) = (-5 + 15)/(2) = 5m//s` `P = overset(vec)(F).overset(vec)(V) = -mgV` `= -100 xx 5 = -500 W`

Discussion

21.	If the energy ( E) ,velocity (v) and force (F) be taken as fundamental quantities,then the dimension of mass will beA. `Ev^2`B. `Ev^-2`C. `Fv^-1`D. `Fv^-2`
Answer» Correct Answer - B Let `mpropE^xv^yF^z` By substituting the following dimensions: `[E]=[ML^2T^-2]`,`[v]=[LT^-1]`,`[F]=[MLT^-2]` and by equating the both sides

Discussion

22.	The dimensions of `a/b` in the equation `P=(a-t^(2))/(bx)` where `P` is pressure, `x` is distance and `t` is time areA. `[M^(2)LT^(-3)]`B. `[MT^(-2)]`C. `[LT^(-3)]`D. `[ML^(3)T^(-1)]`
Answer» Correct Answer - B `[a]=T^(2)` `[X]=L` `[P]=ML^(-1)T^(-2)=T^(2)/[b]L` `[b]=T^(2)/ML^(-1)T^(-2)L=M^(-1)T^(4)` `[a]/[b]=T^(2)/M^(-1)T^(4)=MT^(-2)`

Discussion

23.	If pressure P, velocity V and time T are taken as fundamental physical quantities, the dimensional formula of force ifA. `PV^2T^2`B. `P^-1V^2T^-2`C. `PVT^2`D. `P^-1VT^2`
Answer» Correct Answer - A Let `Fpropp^xV^yT^z` by subsituting the following dimensions: `[P]=[ML^-1T^-2][V]=[LT^-1]`,`[T]=[T]` and comparing the dimension of both sides `x=1`,`y=2`,`z=2`, so `F=PV^2T^2`

Discussion

24.	If the mass time and work are taken as fundamental physical quantities then dimensional formula of lengthA. `[m^(1/2)T^(1)W^(-1/2)]`B. `[M^(-1/2)T^(1)W^(1/2)]`C. `[M^(-1)T^(2)W]`D. none of these
Answer» Correct Answer - B `L=M^(a)T^(b)(ML^(2)T^(-2))^(c)` `a+c=0` ` 2c=1` `c=1/2 a= (-1)/2` ` b=2c=0 rArr b=1`

Discussion

25.	Consider a screw gauge without any zero error. What will be the final reading corresponding to the final state as shown? It is given that the circular head translates P msd in N rotations One msd is equal to 1 mm. A. `(P/N)(2+45/100)`mmB. `(N/P)(2+45/N)`mmC. `P(2/N+45/100)`mmD. `[2+45/100xxP/N]` mm
Answer» Correct Answer - D Nrotations rightarrow P msd ` 1 rotation (100 divisions) rightarrow P/N msd` `45 division rightarrow 1/100xxP/Nxx45 msd` (mm) The reading shows two msd and 45 on the circular theremore reading `= 2mm + 1/100xxP/Nxx45` (mm)

Discussion

26.	The diagram shows part of the vernier scale on a pair of calipers Which reading is correct A. 2.74cmB. 3.10cmC. 3.26cmD. 3.64cm
Answer» Correct Answer - A VS `=4 MS = 2.7` `MS +VS xx LC` ` 2.7 + 0.04= 2.74`

Discussion

27.	A unit positive point charge of mass m is projected with a velocity v inside the tunnel as shown. The tunnel has been made inside a uniformly charged nonconducting sphere. The minimum velocity with which the point charge should be projected such it can it reach the opposite end of the tunnel is equal to A. `[rhoR^2//4mepsilon_0]^1/2`B. `[rhoR^2//24mepsilon_0]^1/2`C. `[rhoR^2//6mepsilon_0]^1/2`D. zero because the initial and the final points are at same potential
Answer» Correct Answer - A If we throw the charged particle just right of the `v` center of the tunnel, the particle will cross the tunnel. Hence applying conservation of `ME` between start point and center of tunnel, `DeltaK+DeltaU=0` or `(0+(1)/(2)mv^(2))+q(V_(f)-V_(i))=0` or `V_(f)=(V_(s))/(2)(3-(r^(2))/(R^(2)))=(pR^(2))/(6epsilon_(0))(3-(r^(2))/(R^(2)))` Hence `r=(R)/(2)` `V_(f)=(pR^(2))/(6epsilon_(0))*(3-(R^(2))/(4R^(2)))=(11pR^(2))/(24epsilon_(0))` `V_(i)=((pR^(2))/(3epsilon_90))` `(1)/(2)mv^(2)=1[(11pR^(2))/(24epsilon_(0))-(pR^(2))/(3epsilon_90)]=(pR^(2))/(3epsilon_(0))[(11)/(24)-(1)/(3)]` `=(pR^(2))/(8epsilon_(0))` or `V=((pR^(2))/(4mepsilon_(0)))^(1//2)` Hence, velocity should be slightly greater than `V`.

Discussion

28.	Two insulting plates are both uniformly charged in such a way that the potential difference between them is `V_2-V_1=20V`. (i.e., plate 2 is at a higher potential). The plates are separated by `d=0.1m` and can be treated as infinity large. An electron is released from rest on the inner surface of plate 1. What is its speed when it hits plate 2? (`e=1.6xx10^-19C`, `m_e=9.11xx10^-31kg`) A. `7.02 xx 10^(12)m//s`B. `1.87 xx10^(6)m//s`C. `32 xx 10^(-19) m//s`D. `2.65 xx 10^(6)m//s`
Answer» Correct Answer - D `(1)/(2) mv^(2)=q Deltav` `V^(2) = (2q Delta V)/(m) =(2xx1.6 xx 10^(-19)xx20)/(9.11 xx 10^(-31))` `V^(2)=7.02 xx 10^(12)` `V=2.65 xx 10^(6)m//s`

Discussion

29.	A few electric field lines for a system of two charges `Q_(1)` and `Q_(2)` fixed at two different points on the `x`-axis are shown in the figure. These lines suggest that (i) `\|Q_(1) \| gt \|Q_(2)\|` (ii) `\|Q_(1)\| lt \|Q_(2)\|` (iii) At a finite distance to the left of `Q_(1)` the electric field is zero (iv) At a finite distance to the right of `Q_(2)` the electric field is zero A. `\|Q_(1)\| gt \|Q_(2)\|`B. `\|Q_(1)\| lt \|Q_(2)\|`C. at a finite distance to the left of `Q(1)` the electric field is zeroD. at a finite distance distance to the right of `Q_(2)` the electric field is zero.
Answer» Correct Answer - A::D

Discussion

30.	What are isotopes?
Answer» The nuclei which have the same atomic number but different mass numbers.

Discussion

31.	What is ‘diffraction of light’? Explain its two types
Answer» The bending of light near the edge of an obstacle or slit and spreading into the region of geometrical shadow is called diffraction of light. Two types of diffraction are: a. Fresnel diffraction: Diffraction pattern in which source of light and screen are kept at finite distance from the slit is called fresnel diffraction. eg: Diffraction of straight edge, small opaque disc, narrow rectangular slit, etc. b. Fraunhofer diffraction: Diffraction pattern in which, the source of light and the screen are effectively at infinite distances from the diffracting system is called Fraunhoffer diffraction. In this diffraction pattern convex lens is used. eg: Diffraction due to single slit, double slit, etc.

31.

What is ‘diffraction of light’? Explain its two types

Answer»

The bending of light near the edge of an obstacle or slit and spreading into the region of geometrical shadow is called diffraction of light.

Two types of diffraction are:

a. Fresnel diffraction: Diffraction pattern in which source of light and screen are kept at finite distance from the slit is called fresnel diffraction.

eg: Diffraction of straight edge, small opaque disc, narrow rectangular slit, etc.

b. Fraunhofer diffraction: Diffraction pattern in which, the source of light and the screen are effectively at infinite distances from the diffracting system is called Fraunhoffer diffraction. In this diffraction pattern convex lens is used.

eg: Diffraction due to single slit, double slit, etc.

Discussion

32.

Distinguish between ‘paramagnetic’ and ‘ferromagnetic’ substances.

Answer»

No.	Paramagnetic substance	Ferromagnetic substance
i.	It is weakly attracted by a magnet.	It is strongly attracted by a magnet.
ii.	When kept in a non-uniform magnetic field, it shows moderate tendency to move from weaker to the stronger part of the field.	When kept in a non-uniform magnetic field, it shows strong tendency to move from weaker to the stronger part of the field.
iii.	When kept in an external magnetic field it becomes weakly magnetised, and the direction of magnetic moment acquired will be same as that of the field.	When kept in an external magnetic field it becomes strongly magnetised, and the direction of magnetic moment acquired will be same as that of the field.
iv.	When the external magnetic field is removed, the paramagnetic substance loses its magnetism.	When the external magnetic field is removed, the ferromagnetic substance retains magnetism permanently.
v.	They cannot be converted into ferromagnetic substances.	When heated above curie temperature, they become paramagnetic substances.
vi	Every atom has some magnetic dipole moment but resultant dipole moment is zero.	The resultant magnetic dipole moment is greater.
vii	They can be temporarily magnetised in external magnetic field.	They can be permanently magnetised.

Discussion

33.	Mention one need for modulation.
Answer» 1. To reduce the size of the antenna 2. Effective power radiated by the antenna 3. Mixing up of signals from different transmitters

33.

Mention one need for modulation.

Answer»

1. To reduce the size of the antenna

2. Effective power radiated by the antenna

3. Mixing up of signals from different transmitters

Discussion

34.	Write any two limitations of Ohm’s law.
Answer» 1. It is not applicable for metallic conductor at very low and very high temperatures. 2. It is not applicable for semiconductors, super conductors, triodes.

34.

Write any two limitations of Ohm’s law.

Answer»

1. It is not applicable for metallic conductor at very low and very high temperatures.

2. It is not applicable for semiconductors, super conductors, triodes.

Discussion

35.	Column I may match with more than one conditions of column II. `{:("Column-I","Column-II"),((A)Ph-CH=CH-Ph,(p)"Ozonolysis followed by reaction with" `NH_2OH` "leads to more than one oxime prouduct"),((B)(CH_3)_2C=CH-undersetunderset(CH_3)(\|)CH-Cl,(q)"Can exhibit geometrical isomers"),(( C)CH_2=CH-CH=CH_2,(r)"Compounds with this structure formula can be separated into different fractions upon fractional distillation"),((D)OHC-undersetunderset(OH)(\|)(CH)CH-undersetunderset(OH)(\|)(CH)-CHO,(s)"is capable of showing steroisomerism"),(,(t)"On hydrogenation it gives more than one product"):}`
Answer» Correct Answer - A-p,q,r,s ; B-p,s,t ; C-p ; D-r,s,t (A)`Ph-CH=CH-Phoverset(O_3//Zn)toPh-CHOoverset(NH_2OH)tounderset(("syn/anti"))(Ph-CH=N-OH)` Ph-CH=CH-Ph shows geometrical isomers and can be sepearated by fractional distillation. `Ph-CH=CH-PHh+H_2toPh-CH_2-CH_2-Ph`(one product) (B)`(CH_3)_2C=CH-undersetunderset(CH_3)(\|)CH-Cloverset((O_3//Zn))toCH_3-undersetunderset(O)(\|\|)C-CH_3+CH_3-undersetunderset(Cl)(\|)CH-CHOoverset(NH_2OH)to`more than one oxime `(CH_3)_2C=CH-undersetunderset(CH_3)(\|)CH-Cl+H_2to(CH_3)_2CH-CH_2-undersetunderset(CH_3)(\|)overset()CH-Cl`(more than one product) (D)`OHC-undersetunderset(OH)(\|)overset()CH-undersetunderset(OH)(\|)overset()CH-CHO+H_2toundersetunderset(OH)(\|)CH_2-undersetunderset(OH)(\|)overset()CH-undersetunderset(OH)(\|)overset(**)CH-undersetunderset(OH)(\|)CH_2`(more than one product)

Discussion

36.	Match the following : (More than one option in column-II may match with single option in column I
Answer» Correct Answer - A-p,q,r,s ; B-r ; C-p,r ;D-q a protic acid gives positive test with Na metal a carboxylic functional group gives positive test with `NaHCO_3` a carbonyl group yellow ppt. with 2,4-DNP an alcohol gives positive test with Lucas Reagent.

Discussion

37.	How many alkenes can be hydrogenated to give an alkane with molecular formula `C_4H_10` which give three monochloro derivative on monochlorination.
Answer» Correct Answer - 3 The alkane is n-Butane `CH_3-CH_2-CH_2-CH_3` and total 3 alkenes can be hydrogenated, `CH_3-CH_2-CH=CH_2 " " underset((" cis & trans"))(CH_3-CH=CH-CH_3)`

Discussion

38.	Work in groups and write a paragraph on “Laughter is the best medicine.”
Answer» Laughter is the best Medicine A good laugh heals a lot of hurts. It is a mighty good thing that sets everything straight. It is a powerful antidote to stress, pain and conflict. Nothing works faster to bring your mind and body back into balance than a good laugh. Humour lightens your burden, inspires hope, connects you to others and keeps you grounded, focussed and alert. A good hearty laugh relieves physical tension and stress leaving your muscles relaxed for up to 45 minutes after. It improves the function of blood and increases blood flow, which can help protect you against heart attack and other vascular diseases. Shared laughter is one of the most effective tool. When laughter is shared, it binds people together and increases happiness and intimacy. Therefore, one should always maintain positive attitude in life and keep laughing to stay healthy and happy.

38.

Work in groups and write a paragraph on “Laughter is the best medicine.”

Answer»

Laughter is the best Medicine

A good laugh heals a lot of hurts. It is a mighty good thing that sets everything straight. It is a powerful antidote to stress, pain and conflict. Nothing works faster to bring your mind and body back into balance than a good laugh. Humour lightens your burden, inspires hope, connects you to others and keeps you grounded, focussed and alert. A good hearty laugh relieves physical tension and stress leaving your muscles relaxed for up to 45 minutes after. It improves the function of blood and increases blood flow, which can help protect you against heart attack and other vascular diseases. Shared laughter is one of the most effective tool. When laughter is shared, it binds people together and increases happiness and intimacy. Therefore, one should always maintain positive attitude in life and keep laughing to stay healthy and happy.

Discussion

39.	The elevated activity of amylase in the blood is indication of:A. hepatitisB. muscle dystrophyC. acute pancreatitisD. myocardial infarctionE. stomach disease
Answer» Correct option is C. acute pancreatitis

Discussion

40.	Put the words in the correct order to make sentences. Use a different colour to write the adverbs.1. Was / somebody / there / nearby / standing.2. Came / Anand / to / school / early.3. Softly / Murali / speaks4. Beautifully / the house / have / they / decorated5. English / classes / during / always / we / English / speak.
Answer» 1. There was somebody standing nearby. 2. Anand came to school early. 3. Murali speaks softly. 4. They have decorated the house beautifully. 5. We always speak English during English classes.

40.

Put the words in the correct order to make sentences. Use a different colour to write the adverbs.1. Was / somebody / there / nearby / standing.2. Came / Anand / to / school / early.3. Softly / Murali / speaks4. Beautifully / the house / have / they / decorated5. English / classes / during / always / we / English / speak.

Answer»

1. There was somebody standing nearby.

2. Anand came to school early.

3. Murali speaks softly.

4. They have decorated the house beautifully.

5. We always speak English during English classes.

Discussion

41.	Look at the picture and fill in the blanks with suitable words.1. The car was moving too _______2. The lift is moving _______3. Joanna did her classwork _____4. Keerthi Vasan arrived _____5. Paul _______ plays cricket with his friends.6. Suguna _______ helps her mother at home.
Answer» 1. fast 2. slowly 3. neatly 4. late 5. always 6. often

41.

Look at the picture and fill in the blanks with suitable words.1. The car was moving too ___2. The lift is moving _3. Joanna did her classwork _4. Keerthi Vasan arrived _5. Paul _ plays cricket with his friends.6. Suguna ___ helps her mother at home.

Answer»

1. fast

2. slowly

3. neatly

4. late

5. always

6. often

Discussion

42.	Just then, the richest farmer in the village pushed his way to the _______ of the group. (a) back (b) middle (c) side(d) front
Answer» Correct answer is (d) front

Discussion

43.	It poured and poured and only those of us who have seen the _______ will know what that means. (a) rains (b) showers (c) monsoons(d) cyclones
Answer» (c) monsoons

Discussion

44.	Here was water to be had, and so close to his . (a) field (b) land (c) holding (d) crop
Answer» Correct answer is (c) holding

Discussion

45.	The dry earth soaked up the moisture, as a hungry _______ laps up milk. (a) cat (b) lion (c) puppy (d) monkey
Answer» Correct answer is (c) puppy

Discussion

46.	Name one reagent or one operation to distinguish between: a. `Be(OH)_(2)` and `Ca(OH)_(2)` b. `BeSO_(4)` and `SrSO_(4)` c. `K_(2)CO_(3)` and `KHCO_(3)`
Answer» a. `Be(OH)_(2)` dissolves in alkali, but `Ca(OH)_(2)` does not. b.`BeSO_(4)` is soluble in water while `SrSO_(4)` is not. c. `K_(2)CO_(3)` does not decompose on heating, whereas `KHCO_(3)` decomposes on heating to give `CO_(2)`, which turns limewater milky.

Discussion

47.	What are the various factors due to which the ionisation enthalpy of the main group elements tends to decrease down a group?
Answer» Within the main group elements, the `IE` decreases regularly as we move down the group due to the following two factors: a. Atomic size.On moving down the group, the atomic size increases gradually due to the addition of one new pricipal energy shell at each succeeding element. As a result, the distance of the valence electrons from teh nucleus increses. Consequently, the force of attraction of the nucleus for the valence electrons decreases and hence the ionisation enthalpy decreases. Screening effect. With the addition of new shells, the number of inner electron shells which shield the valence electrons increases. In other words, the shielding effect or the screening effect increases. As the talence electrons further decreases and hence the `IE` decreases.

Discussion

48.	Why sodium cannot be prepared by electrolysis of its aqueous solution?
Answer» The reduction potential of sodium,`Na`,is much lower than that of `H_(2)O`, therefore on electrolysis, water gets reduced to liberate `H_(2)` in preference of `Na^(o+)` ion. Hence, sodium cannot be prepared by electrolysis of its aqueous solution.

Discussion

49.	The first ionisation enthalpy of group `13` elements are : Explain this deviation from the general trend.
Answer» On moving down the group `13` from `B` to `Al`,`IE` decreases as expected due to an increase in atomic size and screening effect which outweigh the effect of increased nuclear charge. However, `IE_(1)` of `Ga` is only slighly higher `(2 kJ mol^(-1))` than that of `Al` while that of `TI` is much higher than those of `Al`,`Ga` and `In`. These deviations are due to : `Al` follows immediately after `s`-block elements and `TI` after d-and f-block elements. These extra `d-` and `f-` electrons do not shield (or screen) the outer shell electrons from the nucleus very effectively. As a result, the valence electrons remain more tightly held by the nucleus and hence larger amount of energy is needed for their removal. This explains why `Ga` has higher `IE` than `Al`. Further on moving down the group from `Ga` to In , the increased shielding effect (due to the presence of additional `4d`-electrons) outweighs the effect of increased nuclear charge `(49-31=18 units)` and hence the `IE_(1)` of In is lower than that of `Ga`. Thereafter, the effect of increased nuclear charge `(81-49=32 units)` outweighs the shielding effect due to the presence of additional `4f` and `5d` electrons and hence the `IE_(1)` of `TI` is higher than that of `In`.

Discussion

50.	Which of the following is correct for various reversible reaction ?A. In case of liq `hArr` gas, systems the equilibrium is attained between both the phases, whether the system is closed or open.B. Boiling point of a liquid is independent of the altitude of the placed of experiment.C. The value of equilibrium constant is independent of concentration terms.D. It a reversible reaction has high value of its equilibrium constant, the reaction quickly attains the equilibrium.
Answer» Correct Answer - C (A) In open system, said equilibrium is not attained. (B) Atomspheric pressure changes with altitude. (C ) `K_(eq)` is the function of temperature only. (D) `K_(eq)` does not give any information about the rate at which the equilibrium is reached.

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

At a wedding, the bride usually wears a ___dress.

The reaction `_(3)^(7)Li+_(1)^(1)H rightarrow _(4)^(7)Be + _(0)^(1)n` is endothermic. Assuming that Li nuclei is free and at rest. What is the minimum kinetic energy ( in keV) of incident proton so that this reaction occurs? Take Q value of this reaction as -1645 keV.

In a sample initially there are equal number of atoms of two radioactive isotopes A and B. 3 days later the number of atoms of A is twice that of B. Half life of B is `1.5` days. What is half life of isotope A? (in days)

In a modified YDSE the sources S of wavelength 5000 A oscillates about axis of setup according to the equation `y=0.5 sin(pi/6)t` where y is in millimeter and t in second. At what time ti will the intensity at P, a point exactly in front of slit `S_(1)` be maximum for the first time?

The spatial distribution of the electric field due to charges `(A,B)` is shown in figure. Which of the following statements is correct? A. `A` is `+ve` and `B-ve` and `|A|gt|B|`B. `A` is `-ve` and `B+ve, |A|=|B|`C. Both are `+ve` but `AgtB`D. Both are `-ve` but `AgtB`

If the sum of two unit vectors is a unit vector, then magnitude of difference is-A. `sqrt(2)`B. `sqrt(3)`C. `(1)/sqrt(2)`D. `sqrt(5)`

Which of the following sets of concurrent force may be in equilibrium?A. `F_1= 3N, F_2= 5N, F_3= 1N`B. `F_1 = 3N, F_2 = 5N, F_3= 9N`C. `F_1 = 3N, F_2= 5N, F_3= 6N`D. `F_1= 3N, F_2= 5N, F_3= 15N`

What is the torque of the force `vecF=(2hati+3hatj+4hatk)N` acting at the point `vecr=(2hati+3hatj+4hatk)m` about the origin? (Note: Tortue, `vectau=vecrxxvecF`)

The magnitudes of vectors `vecA.vecB` and `vecC` are respectively 12,5 and 13 unira and `vecA+vecB=vecC`, then the angle between `vecA` and `vecB` is :

All the pulleys are ideal, string is massless then rate of work done by gravity at the given instant is `(-x xx 10^(2))W` then calculate `x` :

If the energy ( E) ,velocity (v) and force (F) be taken as fundamental quantities,then the dimension of mass will beA. `Ev^2`B. `Ev^-2`C. `Fv^-1`D. `Fv^-2`

The dimensions of `a/b` in the equation `P=(a-t^(2))/(bx)` where `P` is pressure, `x` is distance and `t` is time areA. `[M^(2)LT^(-3)]`B. `[MT^(-2)]`C. `[LT^(-3)]`D. `[ML^(3)T^(-1)]`

If pressure P, velocity V and time T are taken as fundamental physical quantities, the dimensional formula of force ifA. `PV^2T^2`B. `P^-1V^2T^-2`C. `PVT^2`D. `P^-1VT^2`

If the mass time and work are taken as fundamental physical quantities then dimensional formula of lengthA. `[m^(1/2)T^(1)W^(-1/2)]`B. `[M^(-1/2)T^(1)W^(1/2)]`C. `[M^(-1)T^(2)W]`D. none of these

Consider a screw gauge without any zero error. What will be the final reading corresponding to the final state as shown? It is given that the circular head translates P msd in N rotations One msd is equal to 1 mm. A. `(P/N)(2+45/100)`mmB. `(N/P)(2+45/N)`mmC. `P(2/N+45/100)`mmD. `[2+45/100xxP/N]` mm

The diagram shows part of the vernier scale on a pair of calipers Which reading is correct A. 2.74cmB. 3.10cmC. 3.26cmD. 3.64cm

What are isotopes?

What is ‘diffraction of light’? Explain its two types

Distinguish between ‘paramagnetic’ and ‘ferromagnetic’ substances.

Mention one need for modulation.

Write any two limitations of Ohm’s law.

Match the following : (More than one option in column-II may match with single option in column I

How many alkenes can be hydrogenated to give an alkane with molecular formula `C_4H_10` which give three monochloro derivative on monochlorination.

Work in groups and write a paragraph on “Laughter is the best medicine.”

The elevated activity of amylase in the blood is indication of:A. hepatitisB. muscle dystrophyC. acute pancreatitisD. myocardial infarctionE. stomach disease

Look at the picture and fill in the blanks with suitable words.1. The car was moving too ___2. The lift is moving _3. Joanna did her classwork _4. Keerthi Vasan arrived _5. Paul _ plays cricket with his friends.6. Suguna ___ helps her mother at home.

Just then, the richest farmer in the village pushed his way to the _______ of the group. (a) back (b) middle (c) side(d) front

It poured and poured and only those of us who have seen the _______ will know what that means. (a) rains (b) showers (c) monsoons(d) cyclones

Here was water to be had, and so close to his . (a) field (b) land (c) holding (d) crop

The dry earth soaked up the moisture, as a hungry _______ laps up milk. (a) cat (b) lion (c) puppy (d) monkey

Name one reagent or one operation to distinguish between: a. `Be(OH)_(2)` and `Ca(OH)_(2)` b. `BeSO_(4)` and `SrSO_(4)` c. `K_(2)CO_(3)` and `KHCO_(3)`

What are the various factors due to which the ionisation enthalpy of the main group elements tends to decrease down a group?

Why sodium cannot be prepared by electrolysis of its aqueous solution?

The first ionisation enthalpy of group `13` elements are : Explain this deviation from the general trend.

Explore topic-wise InterviewSolutions in Current Affairs.

At a wedding, the bride usually wears a ___dress.

The reaction `_(3)^(7)Li+_(1)^(1)H rightarrow _(4)^(7)Be + _(0)^(1)n` is endothermic. Assuming that Li nuclei is free and at rest. What is the minimum kinetic energy ( in keV) of incident proton so that this reaction occurs? Take Q value of this reaction as -1645 keV.

In a sample initially there are equal number of atoms of two radioactive isotopes A and B. 3 days later the number of atoms of A is twice that of B. Half life of B is `1.5` days. What is half life of isotope A? (in days)

In a modified YDSE the sources S of wavelength 5000 A oscillates about axis of setup according to the equation `y=0.5 sin(pi/6)t` where y is in millimeter and t in second. At what time ti will the intensity at P, a point exactly in front of slit `S_(1)` be maximum for the first time?

The spatial distribution of the electric field due to charges `(A,B)` is shown in figure. Which of the following statements is correct? A. `A` is `+ve` and `B-ve` and `|A|gt|B|`B. `A` is `-ve` and `B+ve, |A|=|B|`C. Both are `+ve` but `AgtB`D. Both are `-ve` but `AgtB`

If the sum of two unit vectors is a unit vector, then magnitude of difference is-A. `sqrt(2)`B. `sqrt(3)`C. `(1)/sqrt(2)`D. `sqrt(5)`

Which of the following sets of concurrent force may be in equilibrium?A. `F_1= 3N, F_2= 5N, F_3= 1N`B. `F_1 = 3N, F_2 = 5N, F_3= 9N`C. `F_1 = 3N, F_2= 5N, F_3= 6N`D. `F_1= 3N, F_2= 5N, F_3= 15N`

What is the torque of the force `vecF=(2hati+3hatj+4hatk)N` acting at the point `vecr=(2hati+3hatj+4hatk)m` about the origin? (Note: Tortue, `vectau=vecrxxvecF`)

The magnitudes of vectors `vecA.vecB` and `vecC` are respectively 12,5 and 13 unira and `vecA+vecB=vecC`, then the angle between `vecA` and `vecB` is :

All the pulleys are ideal, string is massless then rate of work done by gravity at the given instant is `(-x xx 10^(2))W` then calculate `x` :

If the energy ( E) ,velocity (v) and force (F) be taken as fundamental quantities,then the dimension of mass will beA. `Ev^2`B. `Ev^-2`C. `Fv^-1`D. `Fv^-2`

The dimensions of `a/b` in the equation `P=(a-t^(2))/(bx)` where `P` is pressure, `x` is distance and `t` is time areA. `[M^(2)LT^(-3)]`B. `[MT^(-2)]`C. `[LT^(-3)]`D. `[ML^(3)T^(-1)]`

If pressure P, velocity V and time T are taken as fundamental physical quantities, the dimensional formula of force ifA. `PV^2T^2`B. `P^-1V^2T^-2`C. `PVT^2`D. `P^-1VT^2`

If the mass time and work are taken as fundamental physical quantities then dimensional formula of lengthA. `[m^(1/2)T^(1)W^(-1/2)]`B. `[M^(-1/2)T^(1)W^(1/2)]`C. `[M^(-1)T^(2)W]`D. none of these

Consider a screw gauge without any zero error. What will be the final reading corresponding to the final state as shown? It is given that the circular head translates P msd in N rotations One msd is equal to 1 mm. A. `(P/N)(2+45/100)`mmB. `(N/P)(2+45/N)`mmC. `P(2/N+45/100)`mmD. `[2+45/100xxP/N]` mm

The diagram shows part of the vernier scale on a pair of calipers Which reading is correct A. 2.74cmB. 3.10cmC. 3.26cmD. 3.64cm

What are isotopes?

What is ‘diffraction of light’? Explain its two types

Distinguish between ‘paramagnetic’ and ‘ferromagnetic’ substances.

Mention one need for modulation.

Write any two limitations of Ohm’s law.

Match the following : (More than one option in column-II may match with single option in column I

How many alkenes can be hydrogenated to give an alkane with molecular formula `C_4H_10` which give three monochloro derivative on monochlorination.

Work in groups and write a paragraph on “Laughter is the best medicine.”

The elevated activity of amylase in the blood is indication of:A. hepatitisB. muscle dystrophyC. acute pancreatitisD. myocardial infarctionE. stomach disease

Look at the picture and fill in the blanks with suitable words.1. The car was moving too _______2. The lift is moving _______3. Joanna did her classwork _____4. Keerthi Vasan arrived _____5. Paul _______ plays cricket with his friends.6. Suguna _______ helps her mother at home.

Just then, the richest farmer in the village pushed his way to the _______ of the group. (a) back (b) middle (c) side(d) front

It poured and poured and only those of us who have seen the _______ will know what that means. (a) rains (b) showers (c) monsoons(d) cyclones

Here was water to be had, and so close to his . (a) field (b) land (c) holding (d) crop

The dry earth soaked up the moisture, as a hungry _______ laps up milk. (a) cat (b) lion (c) puppy (d) monkey

Name one reagent or one operation to distinguish between: a. `Be(OH)_(2)` and `Ca(OH)_(2)` b. `BeSO_(4)` and `SrSO_(4)` c. `K_(2)CO_(3)` and `KHCO_(3)`

What are the various factors due to which the ionisation enthalpy of the main group elements tends to decrease down a group?

Why sodium cannot be prepared by electrolysis of its aqueous solution?

The first ionisation enthalpy of group `13` elements are : Explain this deviation from the general trend.

Look at the picture and fill in the blanks with suitable words.1. The car was moving too ___2. The lift is moving _3. Joanna did her classwork _4. Keerthi Vasan arrived _5. Paul _ plays cricket with his friends.6. Suguna ___ helps her mother at home.