100525 + Interview Questions in GENERAL QA IN GENERAL AWARENESS

1.	CONSIDER THE PROCESS ON A THERMODYNAMIC SYSTEM SHOWN IN FIGURE.
Answer» Work done= PV See the graph: At first the V values are increasing but P values are decreasing. So work done decreases first. Then both the V and P values are increasing, thus the work done increases. So the answer is (D).

1.

CONSIDER THE PROCESS ON A THERMODYNAMIC SYSTEM SHOWN IN FIGURE.

Answer»

Work done= PV

See the graph:

At first the V values are increasing but P values are decreasing. So work done decreases first.

Then both the V and P values are increasing, thus the work done increases.

So the answer is (D).

Discussion

2.	How would you explain the lower atomic radii of `Ga` as compared to `Al`?
Answer» The lower atomic radius of `Ga` as compared to `Al` can be explained on the basis of their electronic configuration.Aluminium has noble gas core beneath the valence shell electrons, whereas in gallium, fully filled lesser shielding `3d` electrons are present in-between the valence electrons and noble gas core. As a result, the force of attraction experienced by the valence shell electrons increases and hence the atomic radius at `Ga` decreases.

Discussion

3.	`Cl_(2)` and `F_(2)` are added to a solution containing `1M` eaCHM of `Cl^(c-)` and `Br^(c-)` . What reaction will occur ?
Answer» The reduction potential of halogen in the decreasing order is as follows`:` `F_(2)gtCl_(2)gtBr_(2)gtI_(2)`. So reaction occurs `:` `F_(2)+2Cl^(c-)rarr 2F^(c-)+Cl_(2) (EMF=+ve)`

Discussion

4.	How the reduction potential of an electrode can be decreased?
Answer» It can be decreased either by decreasing metal ion concentration, `i.e., [M^(n+)]` or by decreasing temperature `T.` `M^(n+)+n e^(-) rarr M` `E_(M^(n+)//M)=E_(M^(n+)//M)^(c-)-(RT)/(nF)ln (1)/([M^(n+)])` `=E_(M^(n+)//M)^(c-)+(RT)/(nF)ln[M^(n+)]`

Discussion

5.	What would happen if no salt bridge is used in electroCHMemical cell ?
Answer» For example, in a `Zn-Cu` cell, the `Zn^(2+)` formed by the oxidation of `Zn` will accumulate in cathode. So due to the accumulation of CHMarges the current stops flowing . However, inner circuit is not completed.

Discussion

6.	Give a chemical reaction for which ΔH = ΔU.
Answer» 2H_(g) ⇌ H_2(g) + I_2(g)

Discussion

7.	The size of isoelectronic species `F^(ɵ)`, `Ne`, and `Na^(o+)` is affected by
Answer» The size of the isoelectronic ions depends upon the nuclear charge `(Z)`. As the nuclear charge increases the size decreases. For example, `F^(ө)(+9)gtNe(+10)gtNa^(ө)(+11)`. Therefore, statement `(a)` is correct while all other statements are wrong.

Discussion

8.	Which one of the following statements is incorrect in relation to ionisation enthalpy?
Answer» d. It is difficult to remove electrons from `1s` orbitals than `2s`-orbital, since 1s orbital is nearer to the nucleus and is much move penetrated into the nucleus than `2s`orbitals. Hence, lower the value of `n` more difficult is to remove electrons from orbital having higher value of `n`.

Discussion

9.	Between CO & CO2, which diffuses faster?
Answer» CO diffuses faster.

Discussion

10.	Explain the following reaction: a. Silicon is heated with methyl chloride at high temperature in the presence of copper. b. Silicon dioxide is treated with hydrogen fluoride. c. `CO` is heated with `ZnO`. d. Hydrated alumina is treated with aqueous `NaOH` solution.
Answer» a. A mixture of mono-and di-acid trimethylchloro silanes alongwith a small amount of tetramethyl silance is formed. `Si+CH_(3)Clunderset("373 K")overset("Cu powder")to CH_(3)SiCl_(3)+(CH_(3))_(2)SiCl_(2)+(CH_(3))_(3)SiCl+(CH_(3))_(4)Si` b. `SiO_(2)`, reacts with `HF` on heating to form silicon tetrafluoride which dissolves in HF to form hydroflourosilicic acid. `SiO_(2)+4HFto underset("tetrafluoride")underset("Silicon")(SiF_(4))+H_(2)O` `SiF_(4)+2HFto underset("(soluble)")underset("Hydrofluorosilicic acid")(H_(2)SiF_(6))` c.`CO+ZnOoverset(Delta)toZn+CO_(2)uarr` d. Hydrated alumina dissolves in aqueous `NaOH` solution to form sodium meta-aluminate. `underset("or bauxite")underset("alumina")underset("Hydrated")(Al_(2)O_(3).2H_(2)O_((s)))+NaOH_((aq))overset(Delta)tounderset("(soluble)")underset("meta-aluminate")underset("Sodium")(2NaAlO_(2))+3H_(2)O or Al_(2)O_(3).2H_(2)O_((s))+2NaOH_((aq))+H_(2)O_((l))overset(Delta)tounderset("Sodium tetrahydro-aluminate(III)")(2Na[Al(OH)_(4)]_((aq)))`

Discussion

11.	What is the use of platinum foil in an `SHE` ?
Answer» It is used for the inflow and outflow of electrons.

Discussion

12.	What are representative elements?
Answer» Elements of s-block and p-block are representative elements.

Discussion

13.	How do isotopes of an element differ from one another?
Answer» Atoms having same atomic number but different atomic masses. OR Isotopes of an element differ only in the number of protons.

13.

How do isotopes of an element differ from one another?

Answer»

Atoms having same atomic number but different atomic masses.

OR

Isotopes of an element differ only in the number of protons.

Discussion

14.	Which oil is used for foam formation in Froth Floatation process : (A) Mustard oil (B) Coconut oil (C) Olive oil (D) Pine oil
Answer» Correct option (D) Pine oil Explanation: In Froth Floatation process pine oil is used for foam formation.

14.

Which oil is used for foam formation in Froth Floatation process : (A) Mustard oil (B) Coconut oil (C) Olive oil (D) Pine oil

Answer»

Correct option (D) Pine oil

Explanation:

In Froth Floatation process pine oil is used for foam formation.

Discussion

15.	What is the S.I. Unit of density?
Answer» Kg/m² or kgm^-3

Discussion

16.	When ferric chloride reacts with aq. NaOH, a .......... coloured ppt is formed with NaCl, whose chemical formula is :.............(A) Brown, Fe(OH)2 (B) Green, Fe(OH)2 (C) Green, Fe(OH)3 (D) Brown, Fe(OH)3
Answer» Correct option (D) Brown, Fe(OH)₃ Explanation: FeCl₃+ aq. 3NaOH → Fe(OH)₃ + 3NaCl Ferric Ferric hydroxide chloride (Reddish brown ppt)

16.

When ferric chloride reacts with aq. NaOH, a .......... coloured ppt is formed with NaCl, whose chemical formula is :.............(A) Brown, Fe(OH)2 (B) Green, Fe(OH)2 (C) Green, Fe(OH)3 (D) Brown, Fe(OH)3

Answer»

Correct option (D) Brown, Fe(OH)₃

Explanation:

FeCl₃+ aq. 3NaOH → Fe(OH)₃ + 3NaCl

Ferric Ferric hydroxide

chloride (Reddish brown ppt)

Discussion

17.	An aqueous solution of sodium acetate has pH greater than 7. Explain with equation.
Answer» Sodium acetate is a salt of a strong base and a weak acid which undergoes hydrolysis to form strong alkaline (basic) solution. Hence the pH is greater than 7. CH₃COONa + H₂O ⇌ CH₃COOH + NaOH

17.

An aqueous solution of sodium acetate has pH greater than 7. Explain with equation.

Answer»

Sodium acetate is a salt of a strong base and a weak acid which undergoes hydrolysis to form strong alkaline (basic) solution. Hence the pH is greater than 7.

CH₃COONa + H₂O ⇌ CH₃COOH + NaOH

Discussion

18.	Give reasons : (i) The stability of +3 oxidation state of 13 group elements decreases down the group. (ii) Boron is used as control rods in nuclear reactors. (iii) Graphite is soft and slippery.
Answer» (i) The stability of +3 oxidation state of group 13 elements decreases down the group due to the inert pair effect on ns² electrons. This is because of the poor shielding effect of electron in ‘d’ and ‘f’ orbitals. (ii) Because it absorbs neutrons (iii) Due to the weak van der waal’s force of attraction between the layers of hexagonal rings.

18.

Give reasons : (i) The stability of +3 oxidation state of 13 group elements decreases down the group. (ii) Boron is used as control rods in nuclear reactors. (iii) Graphite is soft and slippery.

Answer»

(i) The stability of +3 oxidation state of group 13 elements decreases down the group due to the inert pair effect on ns² electrons. This is because of the poor shielding effect of electron in ‘d’ and ‘f’ orbitals.

(ii) Because it absorbs neutrons

(iii) Due to the weak van der waal’s force of attraction between the layers of hexagonal rings.

Discussion

19.	Complete the reaction Zn + 2NaOH → : (A) Zn(OH)2 + H2 (B) Na2ZnO2 + H2 (C) Zn(OH)2 + Na2 (D) Na2ZnO2 + Na2O
Answer» Correct option (B) Na₂ZnO₂ + H₂ Explanation: Zn + 2NaOH →Na₂ZnO₂ + H₂ Zinc Sodium Sodium Hydrogen hydroxide Zincate gas.

19.

Complete the reaction Zn + 2NaOH → : (A) Zn(OH)2 + H2 (B) Na2ZnO2 + H2 (C) Zn(OH)2 + Na2 (D) Na2ZnO2 + Na2O

Answer»

Correct option (B) Na₂ZnO₂ + H₂

Explanation:

Zn + 2NaOH →Na₂ZnO₂ + H₂

Zinc Sodium Sodium Hydrogen hydroxide Zincate gas.

Discussion

20.	A man can swim with velocity v relative to water. He has to cross a river of width d flowing with a velocity `u (u gt v)`. The distance through which he is carried down stream by the river is x. Which of the following statements is correct?A. If he crosses the river in minimum time, `x = (du)/(v)`.B. `x` cannot be less than `(du)/(v)`.C. For x to be minimum, he has to swim in a direction making an angle of `(pi)/(2) + sin^(-1) (v//u)` with the direction of the flow of water.D. x will be maximum if he swims in a direction making an angle of `(pi)/(2) 0 sin^(-1)(v//u)` with the direction of the flow of water.
Answer» Correct Answer - A::C

Discussion

21.	STATEMENT-1: A geostationary satellite must be located in the equatorial plane, i.e, at some point vertically above the equator. STATEMENT-1: The only external force acting on an earth satellite is direted towards the centre of the earth.A. Statement-1 is True, Statement-2 is True, Statement-2 is a correct explanation, for Statement-1.B. Statement-1 is True, Statement-2 is True, Statement-2 is not a correct explanation for Statement-1.C. Statement-1 is True, Statement-2 is False.D. Statement-1 is a False, Statement-2 is True.
Answer» Correct Answer - A

Discussion

22.	STATEMENT-1: A geostationary satellite must be located in the equatorial plane, i.e., at some point vertically above the equator. STATEMENT-2: The only external force acting on an earth satellite is directed towards the centre of the earth. (a) Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-1. (b) Statement-1 is True, Statement-2 is True; Statement-2 is not a correct explanation for Statement-1. (c) Statement-1 is True, Statement-2 is False. (d) Statement-1 is False, Statement-2 is True.
Answer» Correct Answer is: (a) Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-1.

Discussion

23.	An indcutor having self inductance L with its coil resistance R is connected across a battery of emf `elipson`. When the circuit is in steady state t = 0, an iron rod is inserted into the inductor due to which its inductance becomes nL (ngt1). When again circuit is in steady state, the current in it isA. `I lt epsilon//R`B. `I gt epsilon//R`C. `I = epsilon//R`D. None of these
Answer» Correct Answer - C When inductance of coil is changed abruptly, flux it remains same. i.e. `phi=LI=constant`. Since here incuctance will increase on insertion of iron rod, so current will decrease. Now current will increases to attain the steady state value `(E//R)`. During thsi time, inductance (nL) will remain same and p.d. across A and B will also remain same. But as current will change with time so rate of prodution of heat will vary.

Discussion

24.	STATEMENT-1: In an elastic collision in one dimension between two bodies, neither of which was at rest before collision, total momentum remains the same before, during and after the collision. STATEMENT-2: In an elastic collision in one dimension between two bodies, neither of which was at rest before collision, total kinetic energy remains the same before, during and after the collision. (a) Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-1.(b) Statement-1 is True, Statement-2 is True; Statement-2 is not a correct explanation for Statement-1. (c) Statement-1 is True, Statement-2 is False. (d) Statement-1 is False, Statement-2 is True.
Answer» Correct Answer is: (c) Statement-1 is True, Statement-2 is False.

Discussion

25.	A charged particle with charge to mass ratio `((q)/(m)) = (10)^(3)/(19) Ckg^(-1)` enters a uniform magnetic field `vec(B) = 20 hat(i) + 30 hat(j) + 50 hat(k) T` at time t = 0 with velocity `vec(V) = (20 hat(i) + 50 hat(j) + 30 hat(k)) m//s`. Assume that magnetic field exists in large space. The pitch of the helical path of the motion of the particle will beA. `pi//100m`B. `pi//125m`C. `pi//215m`D. `pi//250m`
Answer» Correct Answer - D Pitch= TV cos `theta` `=(1)/(f)V(vec(V)vec(B))/(BV)=(pisqrt(38)xx400)/(10^(4)sqrt(3800))=(4pi)/(10^3)m=(pi)/(250)m`.

Discussion

26.	A charged particle with charge to mass ratio `((q)/(m)) = (10)^(3)/(19) Ckg^(-1)` enters a uniform magnetic field `vec(B) = 20 hat(i) + 30 hat(j) + 50 hat(k) T` at time t = 0 with velocity `vec(V) = (20 hat(i) + 50 hat(j) + 30 hat(k)) m//s`. Assume that magnetic field exists in large space. The frequency (in Hz) of the revolution of the particle in cycles per second will beA. `(10^3)/(pisqrt(38))`B. `(10^4)/(pisqrt(38))`C. `(10^4)/(pisqrt(19))`D. `(10^4)/(2pisqrt(19))`
Answer» Correct Answer - B `f=(qB)/(2 pi m) = (10^3)/(19) xx (sqrt(3800))/(2 pi) = (10^(4))/(pisqrt(38))`.

Discussion

27.	STATEMENT-1: The gravitational potential energy of a solid sphere is negative. STATEMENT-2: Two masses attract each other. (a) Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-1. (b) Statement-1 is True, Statement-2 is True; Statement-2 is not a correct explanation for Statement-1. (c) Statement-1 is True, Statement-2 is False. (d) Statement-1 is False, Statement-2 is True.
Answer» Correct Answer is: (a) Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-1.

Discussion

28.	A charged particle with charge to mass ratio `((q)/(m)) = (10)^(3)/(19) Ckg^(-1)` enters a uniform magnetic field `vec(B) = 20 hat(i) + 30 hat(j) + 50 hat(k) T` at time t = 0 with velocity `vec(V) = (20 hat(i) + 50 hat(j) + 30 hat(k)) m//s`. Assume that magnetic field exists in large space. During the further motion of the particle in the magnetic field, the angle between the magnetic field and velocity of the particleA. remains constantB. increasesC. decreasesD. may increase or decrease
Answer» Correct Answer - A Angle remains constant, because magnitudes of components of velocites along and perpendicular to magnetic field remain constant.

Discussion

29.	STATEMENT-1: The gravitational potential energy of a solid sphere is negative. STATEMENT-2: Two masses attract each other.A. Statement-1 is True, Statement-2 is True, Statement-2 is a correct explanation, for Statement-1.B. Statement-1 is True, Statement-2 is True, Statement-2 is not a correct explanation for Statement-1.C. Statement-1 is True, Statement-2 is False.D. Statement-1 is a False, Statement-2 is True.
Answer» Correct Answer - A

Discussion

30.	STATEMENT-1: The electrostatic potential energy of a sphere with uniformly distributed negative charge is positive. STATEMENT-2: Two similar charges repel each other. (a) Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-1. (b) Statement-1 is True, Statement-2 is True; Statement-2 is not a correct explanation for Statement-1. (c) Statement-1 is True, Statement-2 is False. (d) Statement-1 is False, Statement-2 is True.
Answer» Correct Answer is: (a) Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-1.

Discussion

31.	STATEMENT-1: The electrostatic potential energy of a sphere with uniformly distributed negative charge is positive. STATEMENT-1: Two similar charges repel each other.A. Statement-1 is True, Statement-2 is True, Statement-2 is a correct explanation, for Statement-1.B. Statement-1 is True, Statement-2 is True, Statement-2 is not a correct explanation for Statement-1.C. Statement-1 is True, Statement-2 is False.D. Statement-1 is a False, Statement-2 is True.
Answer» Correct Answer - A

Discussion

32.	STATEMENT-1: When a charged particle eneters a magnetic field from outside, its cannot complete one rotation inside the field. STATEMENT-2: The entry and exit of a charged particle into and out of a uniform magnetic filed are symmetrical.A. Statement-1 is True, Statement-2 is True, Statement-2 is a correct explanation, for Statement-1.B. Statement-1 is True, Statement-2 is True, Statement-2 is not a correct explanation for Statement-1.C. Statement-1 is True, Statement-2 is False.D. Statement-1 is a False, Statement-2 is True.
Answer» Correct Answer - A

Discussion

33.	STATEMENT-1: When an uncharged parallel-plate capacitor is charged by conneting it to a cell, the heat produced in the circuit is equal to the energy stored in the capacitor. STATEMENT-1: The charge on a parallel-plate capacitor means the equal and opposite charges, on its inner surfaces.A. Statement-1 is True, Statement-2 is True, Statement-2 is a correct explanation, for Statement-1.B. Statement-1 is True, Statement-2 is True, Statement-2 is not a correct explanation for Statement-1.C. Statement-1 is True, Statement-2 is False.D. Statement-1 is a False, Statement-2 is True.
Answer» Correct Answer - B

Discussion

34.	STATEMENT-1: When an uncharged parallel-plate capacitor is charged by connecting it to a cell, the heat produced in the circuit is equal to the energy stored in the capacitor. STATEMENT-2: The charge on a parallel-plate capacitor means the equal and opposite charges on its inner surfaces. (a) Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-1. (b) Statement-1 is True, Statement-2 is True; Statement-2 is not a correct explanation for Statement-1. (c) Statement-1 is True, Statement-2 is False. (d) Statement-1 is False, Statement-2 is True.
Answer» Correct Answer is: (b) Statement-1 is True, Statement-2 is True; Statement-2 is not a correct explanation for Statement-1.

Discussion

35.	A steel wire is rigidly fixed along diameter of aluminium ring of radius R as shown. Linear expansion coefficient of steel is half of linear expansion coefficient for aluminium thent he thermal stress developed in steel wire is:A. more than `Ralpha_(Al)trianglethetaY`B. less than `Ralpha_(Al)trianglethetaY`C. Equal to `Ralpha_(Al)trianglethetaY`D. equal to `2Ralpha_(Al)trianglethetaY`
Answer» Stress `=2R[alpha_(al)-alpha_(st)]trianglethetaY` if aluminimum ring is alowed to expand freely So stress `lt2R(alpha_(al))trianglethetaY`

Discussion

36.	Two point charges `q` each placed at a distance `R` from each other in vacuum. The force between is `F_(1)` one of the charges is spread uniformly over the surface of a hemispherical bowl of radius R, while the other is spread uniformly over the volume of a sphere `r(rlt(R)/(2))` and both have a common centre O. the force on the sphere is `(F_(1))/(n)`. then n is
Answer» Correct Answer - 2 `F_(1)=(Kq^(2))/(R^(2))` Field due to shell at centre `=(sigma)/(4epsi_(0))` force `(sigma)/(4epsi_(0))xxq=(q)/(2piR^(2))xx(1)/(4epsi_(0))xxq` `=(q^(2))/(4piepsi_(0)R^(2))xx(1)/(2)=(F_(1))/(2)`

Discussion

37.	Tuberculosis is spread through which medium?(a) Polluted air (b) Polluted food (c) Polluted soil (d) All of these
Answer» Tuberculosis is spread Polluted air, Polluted food and Polluted soil medium.

Discussion

38.	One gram carbohydrate provides(a) 2 calories (b) 5 calories (c) 4 calories (d) 3 calories
Answer» One gram carbohydrate provides 4 calories.

Discussion

39.	The radius of curvature of a converging mirror is 30 cm. At what distance from the mirror should an object be placed so as to obtain a virtual image? (a) infinity (b) 30 cm (c) Between 16 cm and 30 cm (d) Between 0 cm and 15 cm
Answer» Correct option is (d) Between 0 cm and 15 cm

Discussion

40.	If a lens can converge the sun rays at a point 20 cm. away from its optical centre, the power of this lens is — (a) + 2D (b) - 2D (c) + 5D (d) - 51D
Answer» Correct option is (c) + 5D

Discussion

41.	Assertion (A): Hydrochloric acid helps in the digestion of food in the stomach. Reason (R) : Hydrochloric acid creates an acidic medium to activate protein digesting enzymes.(a) Both (A) and (R) are true and (R) is the correct explanation of (A). (b) Both (A) and (R) are true but (R) is not the correct explanation of (A). (c) (A) is true, but (R) is false. (d) (A) is false, but (R) is true.
Answer» (a) Both (A) and (R) are true and (R) is the correct explanation of (A).

Discussion

42.	A small ball of mass `m_(2)` rests on the top of a bigger ball of mass `m_(1)(gtgtm_(2)`. The centre of bigger ball is at height `3r` above ground as shown. The balls are dropped from this situation. If the smaller ball bounces to a height 4 nr from ground after its first collision with bigger ball. find n. (Assume all collisions are elastic).
Answer» Correct Answer - 5 Velocity of ball m, just after collision with ground `u_(1)=sqrt(4gr)` Velocity of ball `m_(2)` at this instant is `u_(2)=-sqrt(4gr)` Velocity of `m_(2)` just after collision between `m_(1)&m_(2)` `V_(2)=-U_(2)+2u_(1)=sqrt(4gr)+2sqrt(4gr)=3sqrt(4gr)` max height bt `m_(2)=2r+(v_(2)^(2))/(2g)=20r`

Discussion

43.	The temperature of an spherical isolated black body falls from `T_(1)` and `T_(2)` in time t them time t isA. `t prop ((1)/(T_(2))-(1)/(T_(1)))`B. `t prop ((1)/(T_(2)^(2))-(1)/(T_(1)^(2)))`C. `t prop ((1)/(T_(2)^(3)) -(1)/(T_(1)^(3)))`D. `t prop ((1)/(T_(2)^(4))-(1)/(T_(1)^(4)))`
Answer» Correct Answer - A Power radiated `P = 4 pi r^(2) sigma T^(4)=-(ms(dT)/(dt))` `-(dT)/(T^(2))=(4 pi r^(2)sigma dt)/(m)=c dt` `-underset(T_(1))overset(T_(2))(int) =ct rArr t=K[(1)/(T_(2)^(3))-(1)/(T_(1)^(3))]`.

Discussion

44.	The temperature of an spherical isolated black body falls from `T_(1)` and `T_(2)` in time t them time t isA. `tprop((1)/(T_(2))-(1)/(T_(1)))`B. `tprop((1)/(T_(2)^(2))-(1)/(T_(1)^(2)))`C. `tprop((1)/(T_(2)^(3))-(1)/(T_(1)^(3)))`D. `tprop((1)/(T_(2)^(4))-(1)/(T_(1)^(4)))`
Answer» Power radiated `P=4pir^(2)sigmaT^(4)=(ms(dT)/(dt))` `-int_(T_(1))^(T_(2))(dT)/(T^(4))=ctimpliest=K[(1)/(T_(2)^(3))-(1)/(T_(1)^(2))]`

Discussion

45.	A rod of uniform cross-section but non-uniform thermal conductivity which vary as `k=k_(0)(x^(2))/(L^(2))(1lexleL)` (as shown in figure) is kept between fixed temperature difference for a long time. Select the correct options(s)A. B. C. D.
Answer» `i=(k_(0)x^(2))/(L^(2))A(dT)/(dx)impliesint_(T_(H))^(T)dT=-(iL^(2))/(k_(0)A)int_(1)^(x)(dx)/(x^(2))` `T-T_(H)=(iL^(2))/(k_(0)A)[(1)/(x)]_(1)^(2)`

Discussion

46.	A rod of uniform cross-section but non-uniform thermal conductivity which vary as `k=k_(0)(x^(2))/(L^(2))(1lexleL)` (as shown in figure) is kept between fixed temperature difference for a long time. Select the correct options(s)A. B. C. D.
Answer» Correct Answer - A::D `I = (k_(0)x^(2))/(L^(2))A(dT)/(dx)rArr underset(T_(H))overset(T)(int)dT=(iL^(2))/(k_(0)A) underset(l)overset(x)(int) (dx)/(x^(2))` `T-T_(H)=(iL^(2))/(k_(0)A)[(1)/(x)]_(1)^(x)`.

Discussion

47.	Why is the resistance of a wire vary with its area of cross - section?
Answer» Resistance: Resistance of a wire is directly proportional to the length of the conductor and inversely proportional to the area of the cross-section. That is, \(R\propto\frac{L}{A}\) Introducing a constant of proportionality, \(R=\frac{\rho L}{A}\)(where \(\rho\) is the resistivity of the material.) 1. From the formula, we can observe that the resistance is inversely proportional to the cross-section area. 2. Hence, the resistance increases as the cross-section area decreases and vice-versa.

47.

Why is the resistance of a wire vary with its area of cross - section?

Answer»

Resistance: Resistance of a wire is directly proportional to the length of the conductor and inversely proportional to the area of the cross-section.

That is, \(R\propto\frac{L}{A}\)

Introducing a constant of proportionality,

\(R=\frac{\rho L}{A}\)(where \(\rho\) is the resistivity of the material.)

1. From the formula, we can observe that the resistance is inversely proportional to the cross-section area.
2. Hence, the resistance increases as the cross-section area decreases and vice-versa.

Discussion

48.	Howard Gardner has proposed many types of intelligences except ....... . a. linguistic b. creative c. intrapersonal d. interpersonal
Answer» Answer is b. creative

Discussion

49.	........... is a dynamic situation-specific reaction to stress. a. Appraisal b. Coping c. Situational support d. Assertiveness
Answer» Answer is (b) Coping

Discussion

50.	As per the General Adaptation Syndrome, the individual is ready for fight or flight in the ........ stage. a. resistance b. burnout c. alarm reaction d. exhaustion
Answer» c. alarm reaction

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

CONSIDER THE PROCESS ON A THERMODYNAMIC SYSTEM SHOWN IN FIGURE.

How would you explain the lower atomic radii of `Ga` as compared to `Al`?

`Cl_(2)` and `F_(2)` are added to a solution containing `1M` eaCHM of `Cl^(c-)` and `Br^(c-)` . What reaction will occur ?

How the reduction potential of an electrode can be decreased?

What would happen if no salt bridge is used in electroCHMemical cell ?

Give a chemical reaction for which ΔH = ΔU.

The size of isoelectronic species `F^(ɵ)`, `Ne`, and `Na^(o+)` is affected by

Which one of the following statements is incorrect in relation to ionisation enthalpy?

Between CO &amp; CO2, which diffuses faster?

Explain the following reaction: a. Silicon is heated with methyl chloride at high temperature in the presence of copper. b. Silicon dioxide is treated with hydrogen fluoride. c. `CO` is heated with `ZnO`. d. Hydrated alumina is treated with aqueous `NaOH` solution.

What is the use of platinum foil in an `SHE` ?

What are representative elements?

How do isotopes of an element differ from one another?

Which oil is used for foam formation in Froth Floatation process : (A) Mustard oil (B) Coconut oil (C) Olive oil (D) Pine oil

What is the S.I. Unit of density?

When ferric chloride reacts with aq. NaOH, a .......... coloured ppt is formed with NaCl, whose chemical formula is :.............(A) Brown, Fe(OH)2 (B) Green, Fe(OH)2 (C) Green, Fe(OH)3 (D) Brown, Fe(OH)3

An aqueous solution of sodium acetate has pH greater than 7. Explain with equation.

Give reasons : (i) The stability of +3 oxidation state of 13 group elements decreases down the group. (ii) Boron is used as control rods in nuclear reactors. (iii) Graphite is soft and slippery.

Complete the reaction Zn + 2NaOH → : (A) Zn(OH)2 + H2 (B) Na2ZnO2 + H2 (C) Zn(OH)2 + Na2 (D) Na2ZnO2 + Na2O

Tuberculosis is spread through which medium?(a) Polluted air (b) Polluted food (c) Polluted soil (d) All of these

One gram carbohydrate provides(a) 2 calories (b) 5 calories (c) 4 calories (d) 3 calories

The radius of curvature of a converging mirror is 30 cm. At what distance from the mirror should an object be placed so as to obtain a virtual image? (a) infinity (b) 30 cm (c) Between 16 cm and 30 cm (d) Between 0 cm and 15 cm

If a lens can converge the sun rays at a point 20 cm. away from its optical centre, the power of this lens is — (a) + 2D (b) - 2D (c) + 5D (d) - 51D

The temperature of an spherical isolated black body falls from `T_(1)` and `T_(2)` in time t them time t isA. `t prop ((1)/(T_(2))-(1)/(T_(1)))`B. `t prop ((1)/(T_(2)^(2))-(1)/(T_(1)^(2)))`C. `t prop ((1)/(T_(2)^(3)) -(1)/(T_(1)^(3)))`D. `t prop ((1)/(T_(2)^(4))-(1)/(T_(1)^(4)))`

The temperature of an spherical isolated black body falls from `T_(1)` and `T_(2)` in time t them time t isA. `tprop((1)/(T_(2))-(1)/(T_(1)))`B. `tprop((1)/(T_(2)^(2))-(1)/(T_(1)^(2)))`C. `tprop((1)/(T_(2)^(3))-(1)/(T_(1)^(3)))`D. `tprop((1)/(T_(2)^(4))-(1)/(T_(1)^(4)))`

A rod of uniform cross-section but non-uniform thermal conductivity which vary as `k=k_(0)(x^(2))/(L^(2))(1lexleL)` (as shown in figure) is kept between fixed temperature difference for a long time. Select the correct options(s)A. B. C. D.

A rod of uniform cross-section but non-uniform thermal conductivity which vary as `k=k_(0)(x^(2))/(L^(2))(1lexleL)` (as shown in figure) is kept between fixed temperature difference for a long time. Select the correct options(s)A. B. C. D.

Why is the resistance of a wire vary with its area of cross - section?

Howard Gardner has proposed many types of intelligences except ....... . a. linguistic b. creative c. intrapersonal d. interpersonal

........... is a dynamic situation-specific reaction to stress. a. Appraisal b. Coping c. Situational support d. Assertiveness

As per the General Adaptation Syndrome, the individual is ready for fight or flight in the ........ stage. a. resistance b. burnout c. alarm reaction d. exhaustion

Between CO & CO2, which diffuses faster?