Explore topic-wise InterviewSolutions in Current Affairs.

This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.

1.

In a potentiometer whose wire resistance is `10Omega`. The potential fall per `cm` is `V "volts"` is reduced to `(V)/(4)"volt"//cm`. The resistance that must be connected in series with the potentiometer wire isA. `40Omega`B. `30Omega`C. `20Omega`D. `10Omega`

Answer» Correct Answer - A
`(V)/((V)/(4))=(R^(1))/(10)implies R^(1)=40Omega`
2.

Statements about Enzyme Inhibitor Drugs are given below : (A) There are Competitive and Non-competitive inhibitor drugs. (B) These can bind at the active sites and allosteric sites. (C) Competitive Drugs are allosteric site blocking drugs. (D) Non-competitive Drugs are active site blocking drugs. Choose the correct answer from the options given below : (A) (A), (D) only (B) (A), (C) only (C) (A), (B) only (D) (A), (B), (C) only

Answer»

Correct option is (C) (A), (B) only 

Enzyme inhibitors can be competitive inhibitors (inhibit the attachment of substrate on active site of enzyme) and non-competitive inhibitor (changes the active site of enzyme after binding at allosteric site.)

3.

The balancing lengths on a potentiometer wire are `800cm` and `600cm` when two cells of emfs `E_(1)` and `E_(2)` are connected in the secondary circuit first to help each other and next to oppose each other, then `(E_(1))/(E_(2))=`A. `1//11`B. `14//11`C. `7//1`D. `4//3`

Answer» Correct Answer - C
`(E_(1)+E_(2))/(E_(1)-E_(2))=(l_(1))/(l_(2))implies(E_(1))/(E_(2))=(l_(1)+l_(2))/(l_(1)-l_(2))`
4.

What are the types of scripting language?

Answer»

Types of Scripting Language
PHP.
ASP.NET.
Node. js.
Java.
Ruby.
Perl.
Python.

5.

Write a program to calculate primes less than one hundred prints.

Answer»

#include <stdio.h>

int main()
{
  int i, a = 1, count;
 

  while(a <= 100)
  {
    count = 0;
    i = 2;
    while(i <= a/2)
    {
      if(a%i == 0)
      {
        count++;
break;
      }
      i++;
    }
    if(count == 0 && a != 1 )
    {
printf(" %d ", a);
    }
    a++;
  }
  return 0;
}

6.

Write a program that reads ten integers, and then prints the sum of the even and odd integers separately using suitable messages

Answer»

#include <stdio.h>

void main()
{
int i, num, odd_sum = 0, even_sum = 0;

printf("Enter the value of num\n");
scanf("%d", &num);
for (i = 1; i <= num; i++)
{
if (i % 2 == 0)
even_sum = even_sum + i;
else
odd_sum = odd_sum + i;
}
printf("Sum of all odd numbers = %d\n", odd_sum);
printf("Sum of all even numbers = %d\n", even_sum);
}

output :

7.

Physical or logical arrangement of network is __________(a) Topology(b) Routing(c) Networking(d) Control

Answer» The correct option is (a) Topology

The best I can explain: Topology in networks is the structure or pattern in which each and every node in the network is connected. There are many topologies in networking like bus, tree, ring, star, mesh, and hybrid topology. There is no particular best topology and a suitable topology can be chosen based on the kind of application of the network .
8.

Data communication system spanning states, countries, or the whole world is ________(a) LAN(b) WAN(c) MAN(d) PAN

Answer» Right option is (b) WAN

Best explanation: WAN is the abbreviation for Wide Area Network. This network extends over a large geographical area. WANs are used to connect cities, states or even countries. A wireless connection is required to build a WAN. The best example of WAN is the Internet.
9.

Which network topology requires a central controller or hub?(a) Star(b) Mesh(c) Ring(d) Bus

Answer» The correct answer is (a) Star

Explanation: In star topology, no computer is connected to another computer directly but all the computers are connected to a central hub. Every message sent from a source computer goes through the hub and the hub then forwards the message only to the intended destination computer.
10.

_______ topology requires a multipoint connection.(a) Star(b) Mesh(c) Ring(d) Bus

Answer» Correct answer is (d) Bus

Best explanation: In bus topology, there is a single cable to which all the network nodes are connected. So whenever a node tries to send a message or data to other nodes, this data passes through all other nodes in the network through the cable. It is really simple to install but it’s not secure enough to be used in most of the computer network applications.
11.

To find index error v when the same knitting needle is adjusted between the pole and the image needle the separation between the indices of image needle and mirror was found to be `19.9 cm` Index error for v is .A. `0.1 cm`B. `-0.1 cm`C. `0.2 cm`D. `-0.2 cm`

Answer» Correct Answer - B
`e = 19.9 cm - 20.0 cm = - 0.1 cm`
12.

To find index error for u when a knitting needle of length `20.0cm` is adjusted between pole and object needle the separation between the indices of object needle and mirror was pbserved to be `20.2 cm` Index correction for u is .A. `-0.2 cm`B. `0.2 cm`C. `-0.1 cm`D. `0.1cm`

Answer» Index error (Excess reading) = Obsorved reading Actual reading
`=20.2 - 20.0 = 0.2cm` .
13.

In a certain experiment if `(Q)/(P) = (1)/(10)` in `R` if `192Omega` if used we are getting deflection toward right at `193Omega` again toward rightr but at `194Omega` deflection is toward left the unknown resistance should lie between .A. `19.2` to `19.3Omega`B. `19.3` to `19.4Omega`C. `19` to `20.3Omega`D. `19.4` to `19.5Omega`

Answer» Correct Answer - B
`X=(Q)/(P)(R)=(1)/(10)(193hArr19.3hArr19.4`
14.

Mention some physical quantities which have same dimensions but different units.

Answer»

(i) Angular velocity [M0L0T-1] rad s-1 

(ii) Velocity gradient [M0L0T-1] s-1 

(iii) Frequency [M0L0T-1] Hz

15.

A point charge q is placed at the centre of a cube. What is the flux linked. a with all the faces of the cube? b. with each face of the cube? c. if charge is not at the centre, then what will be the answer of parts a and b ?A. `(piq)/(6(4pi epsilon_(0)))`B. `(q)/(6(4pi epsilon_(0)))`C. `(2piq)/(6(4pi epsilon_(0)))`D. `(4piq)/(6(4pi epsilon_(0)))`

Answer» Correct Answer - d
By Gauss law in electrostatic, electric flux through any closed surface is `(q)/(epsilon_(0))`
If the charge is located at the centre of the cube it is placed symmetrically with respect to each other. `:.` Electric flux through each face is
`(1)/(6) (q)/(epsilon)=(1)/(6) (4piq)/((4pi epsilon_(0)))`
16.

An ideal solenoid of inductance L = 1H. Radius a = 0.5 m and numbers of turns per unit length is 1000 turns/meter. The solenoid is fixed and empty from inside. A wooden whell is co-axially to the solenoid and it is free to rotate about its axis of symmetry without any friction. The weeden wheel has radius b = 1m, moment of inertia 1 = 1 kg `m^(2)`, about its axis of symmetry and is initially stationary. Charge of `1000 muC` is applied uniformly on the periphery of the wheel. Now the solenoid is connected to a voltage source whose emf varies with time as `epsilon = ((2)/(mu_(0)))`t volt. Now switch is on at t = 0. Neglect the resistance of the solenoid and mutual-inductance between the wheel and solenoid. Angular velocity of the wheel at t = 2 sec. will be :-A. 0.5 rad/secB. 1 rad/secC. 2 rad/secD. 4 rad/sec

Answer» Correct Answer - A
As magnetic field is changing induce electric field will be generated
`E_(out)=(a^(2))/(2b)((dB)/(dt))=(250)t`
Torque experienced by the wheel
`tau=(1000xx10^(-6))xx250 txx1=t//4`
`I alpha =(t)/(4)rArr alpha=(t)/(4)`
`(d omega)/(dt)=(t)/(4)rArromega = (t^(2))/(8)`
at `t = 2, omega = (4)/(8) = 0.5 rad//sec`
17.

An ideal solenoid of inductance L = 1H. Radius a = 0.5 m and numbers of turns per unit length is 1000 turns/meter. The solenoid is fixed and empty from inside. A wooden whell is co-axially to the solenoid and it is free to rotate about its axis of symmetry without any friction. The weeden wheel has radius b = 1m, moment of inertia 1 = 1 kg `m^(2)`, about its axis of symmetry and is initially stationary. Charge of `1000 muC` is applied uniformly on the periphery of the wheel. Now the solenoid is connected to a voltage source whose emf varies with time as `epsilon = ((2)/(mu_(0)))`t volt. Now switch is on at t = 0. Neglect the resistance of the solenoid and mutual-inductance between the wheel and solenoid. Now at t =2, switch is suddenly off. The angular velocity of the wheel after switching off will be :A. zeroB. 4 rad/secC. 2 rad/secD. 8 rad/sec

Answer» Correct Answer - A
As the switch is suddenly off, the magnetic field will suddenly become zero. So, an impulsive induced electric field will be generated
`E=(a^(2))/(2b)=((dB)/(dt))`
Impulsive torque will be
`tau = (qE) (b)`
`=(1000xx10^(-6))xx((0.5)^(2))/(2xx1)((dB)/(dt))xx(1)`
`tau=(25)/(2)xx10^(-5)((dB)/(dt))`
Angular impulse `= tau dt = (10^(-3))Delta B = (25)/(2) xx 10^(-5) xx 4000 = 0.5 N-m sec`
`L_(f)=L_(i)+J_(ext)`
`(1)omega_(f)=(1)(0.5)-0.5 =0`.
18.

Figure shows the path of an electron in a region of uniform magnetic field. The path consists of two straight sections, each between a pair of uniformly charged plates and two half circles. The electric field exists only between the plates A. Plate `I` of pair A is at higher potential than plate-`II` of the same pairB. Plate `I` of pair B is at higher potential than plate `II` pf the same pairC. Direction of the magnetic field is out of the page `[o.]`D. Direction of the magnetic field in to the page `[otimes]`

Answer» Correct Answer - A::B::C
Using `-e (vec(V) xx vec(B))` for the regin outside the plates, direction of magnetic field can be found. Inside the plates, net force on the electron is zero hence electric force is opposite to that of magnetic force. Direction of electric field between the plates is opposite to that of direction of forece on the negative (electron) charge.
19.

In the circuit shown in Fig. Sliding contact is moving with uniform velocity towards right. Its value at some instance is `12 (Omega)`. The current in the circuit at this instant of time will be A. 0.5 AB. More than 0.5 AC. Less than 0.5 AD. May be less or more than 0.5A depending on the value of L.

Answer» Correct Answer - B
Since resistor of the circuit is increasing and hence current in the circuit is decreasing so `(di)//(dt)` is negative.
Current in the circuit is given by `i=(6-L(di)/(dt))/(12)`
Since `(di)/(dt)` is negative so the value of numerator will be more than 6V and hence current in the circuit at that instant will be more than 0.5A.
20.

Four capacitors having capacity 1,2,3,4 uF connected in parallel. If 20V battery is connected across the system then find the charge flown through the battery(a) 50 μC(b) 100 μC(c) 150 μC(d) 200 μC

Answer»

Correct option is (d) 200 μC

If 1,2,3,4 uF capacitors are connected in parallel then

Ceq = 1+2+3+4 =10μF

Given: V = 20 volt

So charge flown from the battery

q = 10 x 20 μC

q = 200 μC

21.

The time required for a 50Hz alternating current to increase from zero to `70.7%` of its peak value is-A. 1.5 msB. 10 msC. 20 msD. 14.14 ms

Answer» Correct Answer - A
`(1)/(50 xx 8)`
`(1)/(400) sec = 2.5 ms`
22.

Which of the following diagram represents the variation of electric field vector with time for a circularly polarised light?A. B. C. D.

Answer» Correct Answer - a
When two plane-polarised waves are superimposed then under certain conditions, the resultant light vector rotates with a constant magnitude in a plane perpendicular to the direction of propagation. The tip of the vector traces circle and the light is said to be circularly polarised. To form circularly polarised lighy
`E_(x)=E_(0) sin omega t`
`E_(y)=E_(0) cos omega t= E_(0) sin (omegat+(pi)/(2))`
where `E_(0)` is amplitude.
Resultant amplitude
`|vec(E )|^(2)=E_(0)+ E_(0) +2E_(0).E_(0) cos. (pi)/(2)`
`|vec(E )|=E_(0)sqrt(2)=` constant
23.

Two identical discs are positioned on a vertical axis as shown in the figure. The bottom disc is rotating at angular velocity `omega_(0)` and has rotational kinetic energy `K_(0)`. Change in the rotational kinetic energy of the system isA. `k_(@)//6`B. `-(1//2)k_(@)`C. `-(1//4)k_(@)`D. `k_(@)//8`

Answer» Correct Answer - B
24.

An electric dipole with dipole moment 4 × 10−9 C m is aligned at 30° with the direction of a uniform electric field of magnitude 5 × 104 N C−1. Calculate the magnitude of the torque acting on the dipole.

Answer»

Electric dipole moment, p = 4 × 10−9 C m
Angle made by p with a uniform electric field, θ = 30°
Electric field, E = 5 × 104 N C−1
Torque acting on the dipole is given by the relation, τ = pE sinθ =4×10−9×5×104×sin30=20×10−5×1/2=10−4 Nm
Therefore, the magnitude of the torque acting on the dipole is 10−4 N m.

25.

 Atmosphrere is not electrically neutral. Explain why?

Answer»

Many charges flow to and from earth, over which cosmic rays are a tiny part. For instance, an energetic particle arriving in earths atmosphere will create many particle pair of which some must be capable to leave earth and you have the solar wind A strong voltage at earth would already be notices, since it would charge the mean energy of the electrons that arrive.

26.

The children will not be allowed to come with us if they don’t ________ themselves better. A) direct B) accustom C) behave D) declare E) compose

Answer»

Correct option is C) behave

27.

The local tourist bureau will send you _______ about hotels in the area. A) knowledge B) information C) news D) notice E) advertisement

Answer»

Correct option is B) information

28.

You must obtain ________ from the landowner to fish in this river. A) permit B) freedom C) permission D) right E) allowance

Answer»

Correct option is C) permission

29.

In the figure a carbon resistor has band of different colours on its body. The resistance of the following body is(a) 2.2 kΩ  (b) 3.3 kΩ  (c) 5.6 kΩ  (d) 9.1 kΩ

Answer»

Correct option  (d) 9.1 kΩ

Explanation:

R = 91 × 102 ± 10% ≈ 9.1 kΩ

30.

When he saw those photos, Ebright didn’t shout, ‘Eureka!’ or even, ‘I’ve got it!’ But he believed that, along with his findings about insect hormones, the photos gave him the answer to one of biology’s puzzles: how the cell can ‘read’ the blueprint of its DNA. DNA is the substance in the nucleus of a cell that controls heredity. It determines the form and function of the cell. Thus, DNA is the blueprint for life. Ebright and his college room-mate, James R. Wong, worked all that night drawing pictures and constructing plastic models of molecules to show how it could happen. Together they later wrote the paper that explained the theory. i. Choose the option that shows the picture of the type of task Ebright and Wong were engaged in, as per the extract.a) Option (1) b) Option (2) c) Option (3) d) Option (4)ii. Ebright was perhaps expected to shout ‘Eureka!’ because he had a) realised that he needed a partner to work with to finalise his findings. b) discovered something new and ‘Eureka!’ was a cry to announce it. c) worked hard and was relieved at nearing the end of his project. d) given shape to the teachings of his teachers by choosing this field of science. iii. “Thus, DNA is the blueprint for life”, is another way of saying that the DNA contains a genetic __________. a) experiment b) ultimatum c) takeaway d) planiv. Four newspapers published a headline about Ebright and Wong. Choose the option that published a factually correct headline, as per the extract.Newspappere 1Newspapper 2Newspapper 3Newspapper 4WONG DENIES CONTRIBUTING TO EBRIGHT’S THEORYEBRIGHT COLLABORATES WITH ROOM-MATE WONGWONG AND EBRIGHT EXAGGERATE THEIR THEORYDEFY LOGICEBRIGHT AND WONG’S THEORY PROVED WRONGa) Newspaper 1 b) Newspaper 2 c) Newspaper 3 d) Newspaper 4 v Compound words are those words which are formed by joining two separate words to create a new word with an entirely different meaning. Choose the option that lists the compound words from the above extract. 1. determines 2. blueprint 3. nucleus 4. heredity 5. room-mate a) 1, 3 b) 2, 4 c) 1, 4d) 2, 5

Answer»

i. c 

ii. b 

iii. d 

iv. b 

v. d

31.

The vectors \(\vec A\) and \(\vec B\) are such that |\(\vec A\) +\(\vec B\)| = |\(\vec A\) – \(\vec B\)|. The angle between the two vector is ………(a) 45° (b) 60° (c) 75° (d) 90°

Answer»

(d) 90°

The angle between two vector is always  90°.

32.

Which of the following is not a river with inland drainage?A. RupenB. BanasC. PeriyarD. Saraswati1. D2. C3. A4. B

Answer» Correct Answer - Option 2 : C

The correct answer is Periyar.

  • Rann of Kutch is an inland drainage area.
  • Inland drainage is that drainage in which rivers do not reach an ocean or sea but empty their waters in a lake or an inland sea.
  • Narmada flows between Vindhya and Satpura range. Rivers Luni, Ghaggar, Rupnarain, Medha, etc have inland drainage.
  • The Ghaggar is the most important river of inland drainage.
  • It is a seasonal stream that rises on the lower slopes of the Himalayas and forms a boundary between Haryana and Punjab.
  • It gets lost in the dry sands of Rajasthan near Hanumangarh after traversing a distance of 465 km.
33.

Which of the following was a scientist as well as a great industrialist who founded many industries in India?1. CV Raman2. JC Bose3. Vikram Sarabhai4. Homi Jehangir Bhabha

Answer» Correct Answer - Option 3 : Vikram Sarabhai

The correct answer is ​Vikram Sarabhai.

  • Vikram Sarabhai was a scientist, a great industrialist and a founder of many industries in India.

  • Vikram Ambalal Sarabhai was an Indian physicist and astronomer who started space research and helped generate nuclear power in India.
  • He is universally revered as the Father of the Indian Space Program.
  • Sarabhai Chemicals, Sarabhai glass, Sarabhai Geigy Limited are some of the industries founded by Vikram Sarabhai.
  • He was also the founder of Ahmedabad Textile Industrial Association and Ahmedabad Money Association.
  • He was awarded Padma Bhushan in 1966 and the Padma Vibhushan (posthumously) in 1972.
34.

What is the expanded form of IUCN?

Answer»

International Union for Conservation of Nature and Natural Resources.

35.

List any four advantages of genetically modified crop plants over their Wild/domesticated relatives. 

Answer»

(a) More tolerant to abiotic stress 

(b) Provide better yields of crop 

(c) Reduced post harvest losses 

(d) Increased nutritional value of food.

36.

What is the significance of the slope of regression in a species − area relationship?

Answer»

The slope of regression (z) has a great significance in order to find a species-area relationship. It has been found that in smaller areas (where the species-area relationship is analysed), the value of slopes of regression is similar regardless of the taxonomic group or the region. However, when a similar analysis is done in larger areas, then the slope of regression is much steeper.

37.

How is the presently occurring species extinction different from the earlier mass extinctions?

Answer»

Species extinction occuring at present is due to anthropogenic causes where as the earlier extinction was due to natural causes.

38.

Auxin cause apical dominance this hormone is mainly produces in the apical part of the short the reason for apical dominance by auxins (a) Auxin in apical part of shoot have the ability to bans part the cytokinin from root in the apical part of shoot (b) Cytokinin is not transported to apical part that is why auxin cause apical dominance (c) Both (a) and (b) (d) None of the above

Answer»

Correct Option (a) Auxin in apical part of shoot have the ability to bans part the cytokinin from root in the apical part of shoot 

39.

The sandy coastal plain of 'kanthi' lies in which region of West Bengal?1. Ganga Delta2. Rahr Plain3. Alluvial Plain4. Northern Plain

Answer» Correct Answer - Option 2 : Rahr Plain

The correct answer is Rahr Plain.

  • The sandy coastal plain of 'kanthi' lies in Rahr Plain region of West Bengal.
  • Kanthi or Contai is a city in the Purba Medinipur district.

Rahr Plain
  • It lies between the Chota Nagpur Plateau on the West and the Ganges Delta on the East.
  • Medinipur, Bankura, Birbhum, Purulia, Bardhaman.
Ganga Delta
  • South 24 Paragans, North 24 Paraganas, Howrah, Hoogli.
Alluvial Plain
  • The western part of West Bengal, Jharkhand.
Northern Plain
  • Darjeeling Himalayan hill region, Terai region, Siliguri, South and North Dinajpur, Malda, Alipurduar, Cooch Bihar.
40.

If x2 + y2 = z2 , the value of \(\cfrac{1}{log_{z-y}x}+\cfrac{1}{log_{z+y}}\) is (a) x (b) y (c) x + y (d) 2 

Answer»

Correct option is (d) 2

41.

The value of cos13° is(A) \(\frac{1}{\sqrt{2}}\)(B) - \(\frac{1}{\sqrt{2}}\)(C) \(\frac{1}{2}\)(D) \(\sqrt{2}\)

Answer»

Correct option is: (B) - \(\frac{1}{\sqrt{2}}\)

42.

The equation of the plane passing through the point (-1, 2, 1) and perpendicular to the line joining the points (-3, 1, 2) and (2, 3, 4) is · · · · · ·A. `rdot(5hati+2hatj+2hatk)=1`B. `rdot(5hati+2hatj+2hatk)=-1`C. `rdot(5hati-2hatj+2hatk)=-5`D. `rdot(5hati-2hatj-2hatk)=1`

Answer» Correct Answer - A
Direction ratios of line joining points (-3,1,2) and (2,3,4) are (2+3,3-1,4-2) i.e.,(5,2,2)
Since plane is perpendicular to the line joining the given points therefore direction ratio of normal to the plane are (5, 2, 2).
`therefore` Required equation of plane passing through the point (-1, 2, 1) and having normal with direction ratio (5, 2, 2) is
`a(X-x_(1)+b(y-y_(1))+c(z-z_(1))=0`
`!5(x+1)+2(y-2)+2(z-1)=0`
`!5x+5+2y-4+2z-2=0`
`!5x+2y+2z-1=0`
`!rdot(5ati+2hatj+2hatk)-1=0`
43.

The value of `tan^(-1)1/3+tan^(-1)1/5+tan^(-1)1/7+tan^(-1)1/8` is ……..A. `(11pi)/5`B. `pi/4`C. `pi`D. `(3pi)/4`

Answer» Correct Answer - B
We have ,
`tan^(-1).(1)/(3) + tan^(-1).(1)/(5) + tan^(-1) tan^(-1).(1)/(7) + tan ^(-1).(1)/(8)`
`rArr tan^(-1)(((1)/(3)+(1)/(5))/(1-(1)/(3) xx (1)/(5))) + tan^(-1).(((1)/(7)+(1)/(8))/(1-(1)/(7) xx (1)/(8)))`
`(because tan ^(-1) x + tan^(-1) y = tan^(-1)((x+y)/(1-xy)))`
`= tan^(-1) ((8)/(14)) + tan^(-1)((15)/(55)) = tan^(-1)((4)/(7)) + tan^(-1)((3)/(11))`
`= tan^(-1).(((4)/(7) +(3)/(11))/(1-(4)/(7) xx (3)/(11))) = tan^(-1)((44+21)/(77-21))`
`=tan^(-1)((65)/(65)) = tan^(-1) (1) = (pi)/(4)`
44.

If the lengths of the transverse axis and the latusrectum of a hyperbola are 6 and `(8)/(3)` respectively, then the equation of the hyperbola is . . .A. `4x^(2)-9y^(2)=72`B. `4x^(2)-9y^(2)=36`C. `9x^(2)-4y^(2)=72`D. `9x^(2)-4y^(2)=36`

Answer» Correct Answer - B
We have,
Length of transverse axis 2a = 6`!`a = 3 and length of latusrectum ,`(2b^(2))/a=8/3`
`!2b^(2)=8/3xx3=8!b^(2)=4`
`therefore ` Required fo hyperhbola is
`(x^(2))/(a^(2)) -(y^(2))/(b^(2)) = 1 rArr (x^(2))/(9) - (y^(2))/(4) = 1 rArrr 4x^(2) - 9y^(2) = 36`
45.

In which quadrant is 279° situated ? (A) First (B) Second (C) Third (D) Fourth

Answer»

Correct option is: (D) Fourth

46.

The value of K for which the system of equations x + 2y = 3, 5x + Ky = 15 has infinitely many solutions is – (A) 5 (B) 20 (C) 6 (D) 10

Answer»

Correct answer is (D) 10

47.

Roots of the equation x2 + bx + 45 = 0, b ∈ R lie on the curve |z + 1| = 2√10, where z is a complex number then(1) b2 + b = 12 (2) b2 – b = 30 (3) b2 – b = 36 (4) b2 + b = 30 

Answer»

Answer is (2) b2 – b = 30

Let z = α ± iβ be roots of the equation 

So 2α = –b and α2β2 = 45, (α + 1)2β2 = 40

So (α + 1)2 – α2 = – 5

 2α + 1 = – 5  2α = – 6

so b = 6

hence b2 – b = 30 

48.

Calculate the EMF of the concentration cell at 298 K:Ag/Ag+ (0.005 M)//Ag+ (0.5 M)/Ag. What will be the potential of the above cell. When the concentration of silver ions is changed from 0.005 M to 0.01 M at the same temperature?

Answer»

Given ,

Ag/Ag+ (0.005M) // Ag+ (0.5M)/ Ag(s)

A+ anode Ag → Ag+ (0.005M)+e

A + Cathode Ag(0.5M) + e- → Ag(s)

over all cell reaction - 

Ag+ (0.5M) → Ag+ (0.005)

as we know concentration cell , the standard electrode potential (E°) equal to zero.

using nearest equation --

Ecell = E° - \(\frac{RT}{nF}\) \(ln(\frac{[Ag^+]}{[Ag^+]})\)

∴ Ecell  = 0 - \(\frac{RT}{F}\) \(ln\frac{0.005}{0.5}\)

Ecell  = -0.0591 log 10-2

= 0.0591 x 2

Ecell = 0.1182 v

if concentration of Ag+ change from 0.005 M to 0.01 M

then

Ecell = log \((\frac{0.01}{0.5})\)

= -0.0591 log (0.02)

= (-0.0591) x (-1.699)

Ecell  = 0.1 v

Hence the potential of cell will be 0.1 v

49.

Disease like Dysentery and Malaria are caused by:a) Fungi b) Bacteria c) Protozoa d) Virus

Answer»

Disease like Dysentery and Malaria are caused by Protozoa.

50.

Micro organism use in the baking industry for making breads a) Algae b) Fungi c) Yeast d) Moulds

Answer»

Yeast Micro organism use in the baking industry for making breads.