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5101.

If α, β are the roots of ax2 + bx + c = 0 and −α, γ are the roots of a1x2 + b1x + c1 = 0 then β, γ are roots of Ax2 + x + C = 0, where C-1 =

Answer»

\(\because\) α and ß are roots of ax2 + bx + c = 0

\(\therefore\) α + ß  = -b/a and α ß = c/a

Also, -α & \(\gamma\) are roots of a1x2 + b1x + c1 = 0

\(\therefore\) -α + \(\gamma\) = \(\frac{-b_1}{a_1}\) and -α\(\gamma\) = c1/a1

Again, ß and \(\gamma\) are roots of Ax2 + x + c = 0

\(\therefore\) ß + \(\gamma\) = -1/A ⇒ A = -(ß + \(\gamma\))

and ß\(\gamma\) = C/A

\(\therefore\) C = AB\(\gamma\) = -(ß + \(\gamma\)\(\gamma\) (\(\because\) A = -(ß + \(\gamma\)))

\(\therefore\) C-1 = \(\frac{-1}{ß\gamma(ß+\gamma)}\)

5102.

Find value of ' \( K \) ' such that \( x^{2}+2(K-1) x+k+5=0 \) (a) has \( x=2 \) lying inside the roots (b) has one root less than \( 2 \& \) other greater than 2. (c) has roots of opposite signs. (d) has roots such that 5 lies outside the roots. (e) has both roots greater than 5. (f) has exactly one root in \( (1,3) \).

Answer»

Given quadratic equation is 

\(x^2 + 2(k - 1)x + (k + 5) = 0\)

By comparing with ax2 + bx + c = 0, we obtain

\(a = 1>0, b=2(k - 1)\) & \(c = k + 5\)

Let α and \(\beta \) are roots of quadratic equation .

Let \(f(x) = x^2 + 2(k - 1)x + k + 5\).

(a) Given that \(\alpha < 2 < \beta\)

Required condition are 

(i) \(D < 0\)

(ii) \(a f(2) < 0\)

(i) \(D = b^2 - 4ac > 0\)

⇒ \(4(k - 1)^2 - 4(k + 5) > 0\)

⇒ \(4k^2 - 8k + 4 -4k - 20 > 0\)

⇒ \(4k^2- 12k - 16> 0\)

⇒ \(k^2 - 3k - 4 > 0\)

⇒ \((k - 4)(k + 1) > 0\)

⇒ \(k < -1 \;or\; k> 4\)   .....(1)

(ii) \(a f(2) < 0\)

⇒ \(1.(4 + 4k - 4 + k + 5) < 0\)

⇒ \(5k + 1 < 0\)

⇒ \(k < \frac{-1}5\)   ......(2)

\(\therefore\) From (1) & (2), we get

\(k< - 1\)

⇒ \(k \in (-\infty, -1)\)

(b) Given that \(\alpha < 2 < \beta\)

same as question part (a).

\(\therefore\) \(k \in (-\infty, -1)\).

(c) Quadratic equation has roots of opposite sign.

\(\therefore\) Product of roots = negative < 0.

⇒ \(\frac ca < 0\)

⇒ \(\frac{k + 5}1 < 0\)

⇒ \(k< - 5\)

⇒ \(k \in(-\infty, - 5)\)

(d) Case I: \(\alpha, \beta < 5\)

Required conditions are 

(i) \(D \ge 0\)

(ii) \(a f(5) > 0\)

(iii) \(5 > \frac{-b}{2a}\)

(i) \(D \ge 0\)

⇒ \(4k^2 - 12k - 16 \ge 0\)

⇒ \(k^2 - 3k - 4 \ge 0\)

⇒ \((k - 4) (k + 1) \ge 0\)

⇒ \(k \le -1 \; or\; k \ge 4\)  ....(1)

(ii) \(a f(5) > 0\) 

⇒ \(1(25 + 10k - 10 + 10) > 0\)

⇒ \(25 + 10k > 0\)

⇒ \(k > \frac{-25}{10}\)

⇒ \(k > \frac{-5}2\)    .....(2)

(iii) \(5 > \frac{-b}{2a}\) 

⇒ \(5 > \frac{-2(k - 1)}{2(1)}\)

⇒ \(5 > 1 - k\)

⇒ \(k > - 4\)    ....(3)

From (1), (2) & (3), we obtain

\(k\in(\frac{-5}2 , -1] \cup [4,\infty)\)    .....(4)

Case II: \(\alpha, \beta < 5\)

Required conditions are 

(i) \(D \ge 0\)

(ii) \(a f(5) > 0\)

(iii) \(5 > \frac{-b}{2a}\) 

From (i), we get 

\(k \le -1\;or\; k\ge 4 \)   .....(1b)

From (ii), we get 

\(k > \frac{-5}2\)   .....(2b)

From (iii), we get 

\(k < -4\)   ......(3b)

From(1b), (2b), (3b), we obtain 

\(x\in \phi\)  ....(5)

\(\therefore\) From (4) & (5), we get 

\(x\in (\frac{-5}2, -1] \cup [4, \infty)\).

(e) has both roots greater than 5 is solution of part (d) case II.

\(\therefore\) This case is not possible because solution set is empty set.

\(\therefore\) Both roots of given quadratic equation never be greater than 5.

(f) Quadratic equation has exactly one root in (1, 3).

\(\therefore\) \(f(1) f(3) < 0\)

⇒ \((1 + 2k - 2 + 5 + k) (9 + 6k - 6 + k + 5) < 0\)

⇒ \((3k + 4) (7k + 8) < 0\)

⇒ \(\frac{-4}3 < k < \frac{-8}7\)

⇒ \(k \in (\frac{-4}3, \frac{-8}7)\).

5103.

If an integer p is chosen at random in the interval `0le ple5,` then the probality that the roots of the equation `x^(2)+px+(p)/(4)+(1)/(2)=0` are real is -A. ` (4)/(5)`B. ` (2)/(3)`C. ` (3)/(5)`D. None of these

Answer» Correct Answer - B
`DrArrP^(2)-((p)/(4)+(1)/(2))ge0`
`(p-2)*(p+1)ge0`
`pge-1"or" pge0`
In `0leple5,` possible values of p are 2,3,4,5 Thus , probability `=(4)/(6)=(2)/(3)`
5104.

If α, β are the zeros of the quadratic plynimial p(x) = x2 - (k + 6)x + 2(2k - 1) then the value of k,if α + β = \(\frac12\)αβ, is(a) -7(b) 7(c) -3(d) 3

Answer»

Correct option is: (d) 3

5105.

The roots α and β of the quadratic equation x2 - 5x + 3(k - 1) = 0 are such that αβ = 1. Find the value k.

Answer»

α + β = 5 --- (1) 

α - β = 1 --- (2) 

Solving (1) and (2), we get 

α = 3 and β = 2 

Also αβ = 6 

Or 3(k - 1) = 6 

k - 1 = 2 

k = 3

5106.

If Sin(A+B)=1 and Cos(A-B)=root 3/2, A&gt;B find the acute angles A &amp; B

Answer»

We have Sin (A+B)=1 

(A+B)=sin-1 1

We know sin-1 1 = 90 

A+B=90 --------(1) 

Cos (A-B) =3/2 

A-B=cos-1 3/2 

We know cos-1 3/2=30 

A-B=30 -----------(2) 

Solve (1) & (2) 

A+B=90 

A-B=30 add 

2A=120 

A=60 & B=30

Sin (A+B) = 1 and Cos (A-B) = √3/2  

Sin (A+B) = 1

Sin (A+B) = Sin 90o

A + B = 90o

A = 90o - B  ............. (i)

Cos (A-B) = √3/2 

Cos (A-B) = Cos 30o

A - B = 30o

A = 30o + B  .............(ii)

In equation (i) and (ii),

90o - B = 30o + B

90o - 30o = B + B

60o = 2B

B = 60o/2 = 30o

Putting the value of B is eq (i)

A = 90o - B

 = 90o - 30o

 = 60o

Hence,

A = 60o and B = 30o

5107.

calculate the current in a circuit if 500 c charge passes through it in 10 minutes

Answer»

Charge (Q) = 500 C.

Time(t) = 10 minutes.

= 10 × 60

= 600 seconds.

Using the Formula,

Current = Charge/Time.

⇒ I = Q/t

∴ I = 500/600

⇒ I = 5/6

∴ I = 0.83 A.

5108.

class :        100-120  120-140  140-160   160-180   180-200frequency :10             p              10             q              5       =  60

Answer» By the problem

10+p+10+q+5=60

=>q =35-p

Class .              Mid value.    Freq

100-120.            110                 10

120-140             130                   p

140-160 .            150.                 10

160- 180 .           170.           35 -p

180-200 .             190.               5

Given mean = 145

110*10+130*p+150*10+170*(35-p)+190*5=145*60

=>50p= 1100+1500+5950+950-8700

=>50p=800

=>p =16
5109.

48x2 - 13x -1 = 0

Answer»

48x2 - 13x -1 = 0

48x2 - 16x + 3x - 1 = 0

16x (3x - 1) + 1 (3x - 1) = 0

(16x + 1) (3x - 1) = 0

(16x +1) = 0 or (3x-1) = 0

16x = -1  or  3x = 1

x = -1/16  or   x = 1/3

x = -1/16, 1/3

5110.

in the given figure two triangles ABC and DBC lie on same base of BC such that PQ parallel BA and PR parallel BD.prove that QR parallel AD

Answer» I think you are looking for this question:

Click here: -> https://bit.ly/2EuPdLI
5111.

Three pipes A, B, and C can fill a tank in 12 hours, 15 hours, and 20 hours respectively. If pipe A is opened all the time and pipe B and C are open for one hour each alternately. Pipe B opened first then pipe C opened alternatively. At what time the tank will be full?1. 9 hours2. 8 hours3. 6 hours4. 7 hours5. None of these

Answer» Correct Answer - Option 4 : 7 hours

Given:

Pipe A can fill a tank in = 12 hours

Pipe B can fill a tank in = 15 hours

Pipe C can fill a tank in = 20 hours

Calculation:

Let the total capacity of the tank be LCM (12, 15, 20) = 60 litres

Now,

Tank filled by A in 1 hour = 60/12

⇒ 5 litre/hour

Tank filled by B in 1 hour = 60/15

⇒ 4 litre/hour

Tank filled by C in 1 hour = 60/20

⇒ 3 litre/hour

Now,

According to the question,

For first-hour pipe A and B is opened = (5 + 4) litre

⇒ 9 litre

For second-hour pipe A and C is opened = (5 + 3) litre

⇒ 8

For third-hour pipe A and B is opened = (5 + 4) litre

⇒ 9 litre

For fourth-hour pipe A and C is opened = (5 + 3) litre

⇒ 8

Similarly, So…. On

Now,

We conclude that –

2 hours  =   17 litre

× 3               × 3

6 hours   =    51 litre

Now,

The remaining work = (60 – 51)

⇒ 9 litre

Again 7th hour A and B are opened and fill the remaining tank

⇒ 9/9

⇒ 1 hour

Now,

The tank fills in = (6hour + 1 hour)

⇒ 7 hours

The tank will be fill in 7 hours

5112.

Three pipes A, B and C can fill a tank in 12 hours, 15 hours, and 20 hours respectively. If pipe A is opened all the time and pipe B and C are open for one hour each, alternatively, with pipe A. In how much time the tank will be full?1. 9 hours2. 8 hours3. 6 hours4. 7 hours5. None of these

Answer» Correct Answer - Option 4 : 7 hours

Given:

Pipe A can fill a tank in = 12 hours

Pipe B can fill a tank in = 15 hours

Pipe C can fill a tank in = 20 hours

Calculation:

Let the total capacity of tank be LCM (12, 15, 20) = 60 litres

Now,

Tank filled by A in 1 hour = 60/12 = 5 litres

Tank filled by B in 1 hour = 60/15 = 4 litres

Tank empty by C in 1 hour = 60/20 = 3 litres

Now,

According to the question,

For first hour pipe A and B is opened = (5 + 4) litres = 9 litres

For second hour pipe A and C is opened = (5 + 3) litres = 8 litres

Hence, for every 2 hours, volume filled in the tank = (9 + 8) litres = 17 litres

So, in (2 × 3) = 6 hours,volume of the tank filled = 3 × 17 = 51 litres

The remaining volume to be filled = (60 – 51) = 9 litres

Again in the 7th hour, A and B are opened and fill the remaining tank in time = 9/9 = 1 hour

Now, the time taken to fill the tank = 6 hour + 1 hour = 7 hours

The tank will be fill in 7 hours

5113.

Two pipes A and B can fill a tank in 15 hours and 18 hours, respectively. Both pipes are opened simultaneously to fill the tank. In how many hours will the empty tank be filled?1. \(8 \dfrac{2}{11}\)2. \(7 \dfrac{2}{11}\)3. \(9 \dfrac{2}{11}\)4. \(10 \dfrac{2}{11}\)

Answer» Correct Answer - Option 1 : \(8 \dfrac{2}{11}\)

Given:

Pipe A can fill in 15 hours.

Pipe B can fill in 18 hours.

Calculation:

Tank filled by Pipe A in 1 hour

1/15

Tank filled by Pipe B in 1 hour

1/18

Tank filled by both Pipes in 1 hour

(1/15) + (1/18)

11/90

Time taken By both pipes to fill the tank

90/11

\(\Rightarrow 8\frac{2}{{11}}\;{\rm{hours}}\)

Time taken by both pipes is \(8\frac{2}{{11}}\;{\bf{hours}}\).

5114.

Three pipes can fill a tank in 15 hours, 12 hours and 10 hours, respectively. If all the three pipes are opened simultaneously for 3 hours, then what percentage of the tank will remain unfilled?1. 17%2. 50%3. 33%4. 25%

Answer» Correct Answer - Option 4 : 25%

Given:

Three pipes can fill a tank in 15 hours, 12 hours and 10 hours, respectively. If all the three pipes are opened simultaneously for 3 hours

Concept Used:

Pipe and cistern

Calculation:

Three pipes can fill a tank in 15 hours, 12 hours and 10 hours, respectively

To find the total capacity take lcm of three

Lcm of 15,12 and 10 is 60

Total capacity = 60 unit which is 100%

Efficiency of Pipe A = 60/15 = 4

Efficiency of Pipe B = 60/12 = 5

Efficiency of Pipe C = 60/10 = 6

As per the question,

All three pipes were opened for 3 hours

⇒ (4 + 5 + 6) × 3 

⇒ 45 unit work done

Remaining work

⇒ 60 - 45 = (15/60) × 100 = 25%

 

5115.

A train passes a station that is 270 m long in 90 sec. at a speed of 108 km / hr. The time taken by the train to pass a bird feeder is:1. 45 seconds2. 60 seconds3. 81 seconds4. 55 seconds

Answer» Correct Answer - Option 3 : 81 seconds

Given:

Length of the station = 270 m

Time taken on crossing the station = 90 sec

Speed = 108 km / h

Concept:

Crossing a bird feeder = crossing its own length

Crossing a station = Crossing the combined length of train and station.

Calculations:

Speed of train = 108 km / h = 108 × 5 / 18

⇒ 30 m / s

Let the length of the train be x metres.

Then, (x + 270) / 30 = 90

⇒ x + 270 = 90 × 30

⇒ x + 270 = 2700

⇒ x = 2430

So, time taken by the train to cross the bird feeder

⇒ 2430 / 30

⇒ 81 s

The time taken by the train to cross the bird feeder is 81 seconds.
5116.

A train passes a station that is 270 m long in 90 sec. at a speed of 108 km/hr. The time taken by the train to pass a bird feeder is:1. 45 seconds2. 60 seconds3. 81 seconds4. 55 seconds5. 90 seconds

Answer» Correct Answer - Option 3 : 81 seconds

Given:

Length of the station = 270 m

Time taken on crossing the station = 90 sec

Speed = 108 km/h

Calculations:

Speed of train = 108 km/h = 108 × 5/18

⇒ 30 m/s

Let the length of the train be x metres.

Then, (x + 270)/30 = 90

⇒ x + 270 = 90 × 30

⇒ x + 270 = 2700

⇒ x = 2430

So, time taken by the train to cross the bird feeder

⇒ 2430 /30

⇒ 81 s

The time taken by the train to cross the bird feeder is 81 seconds.
5117.

Solve the equations and select the correct option:3x + 5y = 132x + y = 41. x > y2. x < y3. x = y4. x ≥ Y

Answer» Correct Answer - Option 2 : x < y

Given:

3x + 5y = 12

2x + y = 4

Calculation:

3x + 5y = 13      ….(1)

2x + y = 4      ….(2)

Multipying equation (2) by 5

⇒ 10x + 5y = 20     ….(3)

Subtracting equation 2 from 3

⇒ 10x + 5y = 20 

-3x + 5y = 13     

⇒ 7x = 7

⇒ x = 1

Replacing value of x in equation 1

⇒ 3 + 5y = 13

⇒ 5y = 10

⇒ y = 2

x < y

Common mistake:

While multiplying and adding or subtracting terms changes the constant value should be changed 

5118.

Find the wrong term in the following number series.1150, 1342, 1527, 1705, 1876, 20411. 13422. 15273. 18764. 11505. 2041

Answer» Correct Answer - Option 5 : 2041

Given:

1150, 1342, 1527, 1705, 1876, 2041

Calculation:

1342 – 1150 = 192

1527 – 1342 = 185

1705 – 1527 = 178

1876 – 1705 = 171

2040 – 1876 = 164 

∴ The wrong term is 2041

5119.

The curve of angle of incidence versus angle of deviaton wshown has been plotted for prism. Q. The value of refractive index of the prism used isA. `sqrt(3)`B. `sqrt(2)`C. `sqrt(3)//sqrt(2)`D. `2//sqrt(3)`

Answer» `delta=i+e-A`
`delta_(min)=60^(@)` when `i=e`
`therefore60^(@)=2i-A=2(60^(@))-A` `thereforeA=60^(@)`
`thereforemu=(sin((A+delta_(min))/(2)))/(sin((A)/(2)))=(sin((60+60)/(2)))/(sin((60)/(2)))=sqrt(3)`
5120.

Assertion`:-` In general, heat of neutralization of `CH_(3)COOH` by `NaOH` is less than heat of neutralization of `H_(2)SO_(4)` by `NaOH`. Reason`:-` `H_(2)SO_(4)` is a di basic acid while `CH_(3)COOH` is monobasic acid.A. If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.B. If both Assertion & Reason are True but Reason is not a correct explanation of the Assertiion.C. If Assertion is True but the Reason is False.D. If both Assertion & Reason are False

Answer» Correct Answer - B
5121.

Choose the correct code in which all the molecules have dative `pi` bond. I `- P_(4)O_(10)` , II `- (SiH_(3))_(3) N`. , III `-P_(4)O_(6)` , IV `-BF_(3)`A. I, II, III, IVB. II & IVC. I, III, & IVD. I, II & IV

Answer» Correct Answer - D
Conceptual
5122.

Which of the following displacement occur:A. `Zn+2H^(+)toZn^(2+)+H_(2)uarr`B. `Fe+2Ag^(+)toFe^(2+)+Agdarr`C. `Cu+Fe^(2+)toCu^(2+)+Fedarr`D. `Zn+Pb^(2+)toZn^(2+)+Pbdarr`

Answer» Correct Answer - A::B::D
5123.

Select the correct statement(s) with respect to the `p pi-dpi` dative bond.A. In `(Ph_3Si)_2O`, the Si-O-Si group is nearly linearB. Silanols such as `(CH_3)_3` SiOH are stronger protonic acids then their carbon analogsC. Trisilysl phosphine `(H_3Si)_3` P is planarD. `CIO_4^-` does not polymerise at all

Answer» Correct Answer - ABD
(A)Steric repulsions of bulkier groups and `ppi-dpi` dative bonding favour for a linear Si-O-Si group.
(B)Due to stabilization of the conjugate base anion by O `(ppi)to Si(dpi)`bonding motion.
( C)In is pyramidal because `ppi-dpi` bonding is not effective due to the bigger size of phosphorus atom
(D)Most effective due to small size of chlorine.
5124.

Assertion:- `NO_(3)^(-)` is planar while `NH_(3)` is pyramidal Reason:- N in `NO_(3)^(-)` is `sp^(3)` and in `NH_(3)` it is `sp^(3)` hybridised with one ione pair.A. If both Assertion `&` Reason are True `&` the Reason is a correct explanation of the Assertion.B. If both Assertion `&` Reason are True but Reason is not a correct explanation of the Assertion.C. If Assertion is True but the Reason is False.D. If both Assertion `&` Reason are False.

Answer» Correct Answer - A
5125.

List of Basicity or protocity of an acid.

Answer»

It is number of H+ ions furnished by a molecule of an acid. An acid may be classified according to its basicity. Thus we may have,

(i) Mono basic or Mono protic acids like HCl, HNO3, CH3COOH, HCN etc. 

(ii) Dibasic or Diprotic acids like, H2SO4, H2CO3, H2SO3, H2S etc. 

(iii) Tribasic or Triprotic acids like H3PO4 ,H3AsO4 etc.

5126.

What is Arrhenius Acid? Give its Examples.

Answer»

Arrhenius Acid : Substance which gives H+ ion on dissolving in water (H+ donor) 

Ex: HNO3, HClO4, HCl, HI, HBr, H2SO4, H3PO4 etc.

5127.

The basicity of phosphorous acid is : (A) 1 (B) 2 (C) 3 (D) 4

Answer»

Correct option: (B) 2

Explanation: 

Phosphorous acid has two replaceable H+ ions.

5128.

The characteristics of an acid is : (A) turns blue litmus to red. (B) turns phenolphthalein pink from colourless. (C) decompose carbonates (D) oxy compounds of non-metals

Answer»

Correct option: (A) turns blue litmus to red.

Explanation: 

Statement (A) indicates characteristic of acid.

5129.

Select the suitable reason (s) for higher strength of an acid or base : (A) higher value of Ka or Kb (B) higher extent of ionisation (C) (A) and (B) both (D) Larger number of replaceable H atoms.

Answer»

Correct option: (C) (A) and (B) both

Explanation: 

Ka or Kb and degree of ionisation are the measure of strength of an acid or base.

5130.

Arrhenius theory of acid-base is not applicable in : (A) aqueous solution (B) in presence of water (C) non-aqueous solutions (D) none of the above

Answer»

Correct option: (C) non-aqueous solutions

Explanation: 

Since Arrhenius theory is only applicable to aqueous medium.

5131.

What are the types of Arrhenius acids ?

Answer»

Types of Arrhenius Acid are :

(1) Mono basic acid :  Gives single H+ per molecule e.g HA (HNO3, HClO4, HCl)

(2) Di basic acid : Gives two H+ per molecule e.g H2A(H2SO4, H3PO3)

(3) Tri basic acid : Gives three H+ per molecule e.g H3A(H3PO4)

5132.

Define Arrhenius base.

Answer»

Arrhenius base : Any substance which releases OH (hydroxyl) ion in water (OH ion donor)

  • OH ion is present also in hydrated form of H3O2-, H7O4-, H5O3-
  • First group elements (except Li.) form strong bases
5133.

Which of the following statements is true in aqueous medium?A. `CH_(2)CH_(2)S^(-)` is a stronger base and more nucleophilic than `CH_(3)CH_(2)O^(-)`B. `CH_(3)CH_(2)S` is a stronger base but is less nucleophilic than `CH_(3)CH_(2)O^(-)`C. `CH_(3)CH_(2)S^(-)` is a weaker base but is more nucleophilic than `CH_(3)CH_(2)O^(-)`D. `CH_(3)CH_(2)S^(-)` is a weaker base and less nucleophilic than `CH_(3)CH_(2)O^(-)`

Answer» Correct Answer - C
In protic solvent `CH_(3)CH_(2)S^(-)` is more nucleophilic than
`CH_(3)CH_(2)O`:
5134.

Reema took 5ml of Lead Nitrate solution in a beaker and added approximately 4ml of Potassium Iodide solution to it. What would she observe? A. The solution turned red. B. Yellow precipitate was formed. C. White precipitate was formed. D. The reaction mixture became hot.

Answer»

Correct option is B. Yellow precipitate is formed

The relation between lead nitrate and potassium iodide is an example of precipitation reaction.

Pb (No3)2 + 2 KI  \(\longrightarrow\) PbI2 + 2KNO3 (yellow ppt)

The yellow ppt of load iodide can be recovered by filtration.

Correct option is B. Yellow precipitate is formed

5135.

The average speed of nitrogen molecule is v. if the temperature is doubled and nitrogen molecule dissociate into nitrogen atoms completely then new average speed becoems.A. vB. `sqrt(2)v`C. `2v`D. 4v

Answer» `v_(mg)=sqrt((8)/(pi)(RT)/(M))`
`N_(2)(g)rarr2N(g)`
`((v_(avg))N)/((v_(avg))N_(2))sqrt((28xx2T)/(14xxT))=sqrt(4)=2`
`(v_(avg))_(N)=2v`
5136.

What kind of acid does not completely dissociate?

Answer»

A weak acid is one that does not dissociate completely in solution; this means that a weak acid does not donate all of its hydrogen ions (H+) in a solution.

5137.

A photoelectric plate is initially exposed to a spectrum of hydrogen gas excited to second energy level. Late when the same photoelectric plate is exposed to a spectrum of some unknown hydrogen like gas, excited to second energy level. It is found that the de-Broglie wavelength of the photoelectrons now ejected has increased `sqrt(6.1)` times. For this new gas difference of energies of first Lyman line and Balmer series limit is found to be two times the ionization energy of the hydrogen atom is ground state. Detect the atom and determine the work function of the photoelectric plate.

Answer» For minimum de-Broglie wavelength of electron, the momentum and hence `KE` of electron must be maximum.
Case-I.
When hydrogen spectra is used, for maximum energy of photoelectron
`13.6[(1)/(1^(2))-(1)/(2^(2))]-phi=(1)/(2)mv_(1)^(2) rArr (1)/(2)mv_(1)^(2)=(3)/(4)xx13.6eV-phi`
For unknown gas of atomic no.`z`
`13.6z^(2)[(1)/(1^(2))-(1)/(2^(2))]-phi=(1)/(2)mv_(2)^(2) rArr (1)/(2)mv_(2)^(2)=z^(2)(3)/(4)xx13.6ev-phi`
Comparing the de-Broglie wavelengths
`(lambda_(1))/(lambda_(2))=(h//mv_(1))/(h//mv_(2))=((v_(2))/(v_(1)))`
`rArr ((lambda_(1))/(lambda_(2)))^(2)=((3)/(4)xx13.6-phi)/((3)/(4)xx13.6z^(2)-phi)=(1)/(6.1)`....(`1`)
For the unknown gas
Energy of first lvman line-Energy of Balmer series limit `=2xx(13.6)eV`
`(13.6)z^(2)((3)/(4))-13.6z^(2)((1)/(4))=2(13.6)`
`z^(2)//2=2`, `z=2`
`:. ` Unknown gas is helium
Now from equation (`1`)
`(10.2-phi)/(40.8-phi)=(1)/(6.1)`
`rArr phi=4.2eV`
5138.

Study the following table and answer the questions based on it.Production of various models of mobile phones of a company (in lakhs) per year in given years. ABCD200675494556200848605778201089596387201257797492What was the average production (in lakhs) of mobile phones in 2012?1. 63.752. 54.253. 61.54. 75.5

Answer» Correct Answer - Option 4 : 75.5

According to the given information :

Production of mobile phones in 2012 = 57 + 79 + 74 + 92 = 302.

Number of models = 4 (A, B, C, D)

Average = (Total Production) / (Number of Models)

Average production = 302 / 4 = 75.5.

Hence, the correct answer is "75.5".

5139.

The diameter of a cylindrical piston is 5 cm. The stroke length of the piston is 10 cm. Find the displacement volume, if π = 4.1. 125 cm32. 1000 cm33. 500 cm34. 250 cm3

Answer» Correct Answer - Option 4 : 250 cm3

Concept:

Displacement volume:

It is the volume covered while going from T.D.C to B.D.C. It is given by:

\(\frac{\pi}{4}d^2L\)

where d = diameter of the cylinder and L = stroke length of the piston.

Calculation:

Given:

d = 5 cm, L = 10 cm

Displacement volume:

\(\frac{\pi}{4}d^2L\)

\(\frac{4}{4}\times 5^2\times 10=250\,cm^3\)

The relation mentioned in the question was ambiguous so we have made some assumptions as of now until the question gets clear.

5140.

How many associate banks were merged with the State Bank of India in the year 2017?1. 42. 53. 64. 7

Answer» Correct Answer - Option 2 : 5

The correct answer is 5.

  • 5  associate banks were merged with the State Bank of India in the year 2017.
    • These banks were 
      • State Bank of Bikaner and Jaipur (SBBJ),
      • State Bank of Travancore (SBT),
      • State Bank of Patiala (SBP),
      • State Bank of Mysore (SBM),
      • State Bank of Hyderabad (SBH).

  • The merger was approved by the cabinet in June 2016 to make it a global-sized bank.
    • The government order read “the entire undertaking of SBBJ, SBM, SBT, SBP and SBH shall stand transferred to and vested in the State Bank of India from April 01, 2017.”
    • State Bank of Saurashtra was merged with SBI in 2008.
    • State Bank of Indore was merged with it in 2010.
  • State Bank of India
    • Headquarters- Mumbai, Maharashtra
    • Chairperson- Dinesh Kumar Khara
5141.

Which of the following banks is known as the first development bank of India?1. IDBI2. IFCI3. ICICI4. SFC

Answer» Correct Answer - Option 2 : IFCI

IFCI

  • IFCI, previously Industrial Finance Corporation of India, is a Non-Banking Finance Company in the public sector.
  • Established in 1948 as a statutory corporation, IFCI is currently a company listed on BSE and NSE.
  • IFCI has seven subsidiaries and one associate
5142.

Tesla is a measure of1. Magnetic flux density 2. Electric flux density3. Magnetic potential 4. Electric potential

Answer» Correct Answer - Option 1 : Magnetic flux density 

Tesla (T) is a measure of magnetic flux density.

Electrical potential measures in volts (V).

Magnetic potential measures in Amperes (A).
5143.

Which of the following statements may not be considered as a code of ethics for professional engineers?1. Engineers shall hold paramount the safety, health, and welfare of the public2. Engineers shall extend help to poor workers3. Engineers shall perform services only in areas of their competence4. Engineers shall issue public statements only in an objective and truthful manner.

Answer» Correct Answer - Option 2 : Engineers shall extend help to poor workers

The correct answer is Engineers shall extend help to poor workers.

  • Code of Ethics refers to a set of guidelines to bring about acceptable behaviors in members of a particular group, association or profession.

  • The salient values envisaged in the code of ethics are:
    • Allegiance to the various ideals enshrined in the preamble to the Constitution
    • Apolitical functioning
    • Good governance for the betterment of the people to be the primary goal of civil service
    • Duty to act objectively and impartially
    • Accountability and transparency in decision-making
    • Maintenance of highest ethical standards
    • Merit to be the criteria in the selection of civil servants consistent, however, with the cultural, ethnic and other diversities of the nation
    • Provision of healthy and congenial work environment
    • Communication, consultation, and cooperation in the performance of functions i.e. participation of all levels of personnel in management.
5144.

Mechanical efficiency of a gas turbine as compared to internal combustion reciprocating engine is (a) higher (b) lower (c) same (d) un-predictable.

Answer»

Correct option is (b) lower 

5145.

The air standard efficiency of closed gas turbine cycle is given by (rp = pressure ratio for the compressor and turbine)(a) η = 1 – \(\cfrac{1}{(r_p)^{γ-1}}\)(b) η = 1 – ( rp) γ − 1(c) η = 1 – \(\left(\cfrac{1}{r_p}\right)^{γ-1/γ}\)(d) η = (rp)γ-1/γ - 1

Answer»

(d) η = (rp)γ-1/γ - 1

5146.

With the increase in pressure ratio thermal efficiency of a simple gas turbine plant with fixed turbine inlet temperature (a) decreases (b) increases (c) first increases and then decreases (d) first decreases and then increases.

Answer»

(b) increases 

5147.

The process of abstracting steam at a certain section of the turbine and subsequently using it for heating feed water supplied to the boiler is called (a) Reheating (b) Regeneration (c) Bleeding (d) Binary vapour cycle

Answer»

(b) Regeneration

Regeneration is the process of bleeding steam and using it for feed water heating.

5148.

An inward flow reaction turbine has an external diameter of 1 m and its breadth at inlet is 250 mm. If the velocity of flow at inlet is 2 m/s and 10% of the area of flow is blocked by blade thickness, the weight of water passing through the turbine will be nearly (a) 10 kN/s (b) 14 kN/s (c) 18 kN/s (d) 22 kN/s

Answer»

(b) 14 kN/s 

d1 = 1 m 

b1 = 0.25 m 

VF1 = 2 m/s 

k = 0.9 = coefficient of blade thickness 

Q = k⋅πd1b1VF1 

Q = 0.9 × π × 1 × 0.25 × 2 = 1.413 m3/sec 

Weight of water passing through turbine = ρgQ = 1000 × 9.81 × 1.413 = 14 kN/s

5149.

With which religion are the Dilwara temples associated ?1. Buddhism2. Jainism3. Hinduism & Jainism4. Hinduism

Answer» Correct Answer - Option 2 : Jainism

The correct answer is Jainism.

 

  • The Dilwara Temples or Delvada Temples are a group of svetambara Jain temples located about 2+1⁄2 kilometers from the Mount Abu settlement in Sirohi District, Rajasthan's only hill station.
    • Dilwara temples are associated with the Jainism religion.
  • The earliest were built by Vimal Shah and supposedly designed or at least financed by Vastupala, Jain minister of Dholka.
  • They date between the 11th and 16th centuries, forming some of the most famous monuments in the style of Māru-Gurjara architecture, famous for their use of very pure white marble and intricate marble carvings.
  • They are managed by Seth Shri Kalyanji Anandji, Sirohi and are a pilgrimage place for Jains, and a significant general tourist attraction.
  • Although Jains built many temples at other places in Rajasthan, the Dilwara temples are believed to be the most impressive.

​ 

  • Jain architecture developed largely as an offshoot of Hindu and Buddhist styles.
    • It cannot be accredited with a style of its own. Compared to the number of Hindu temples in India, Jain temples are few and spaced out.
    • The regional styles of Jain temple architecture are easily distinguishable in different parts of the country.
  • Early Jain temple architecture was mostly rock-cut and bricks were hardly used. In later years, however, brick temples were constructed on a large scale.
    • At the same time, they also deviated from Hindu and Buddhist sites to build on their own.
  • The majority of Jain temples in India consist of three core building elements:
    • Image chamber Garbhagriha
    • Hall Mandapa
    • Porch
5150.

If mf is the mass of fuel supplied per kg of air in one second, then the mass of gases leaving the nozzle of turbojet will be(a) (1 – mf ) kg/s(b) \(\cfrac{1}{(1+m_f)}kg/s\) (c) (1 + mf ) kg/s(d) \(\cfrac{1}{(1-m_f)}kg/s\)

Answer»

(c) (1 + mf ) kg/s

For turbojet engine, total mass of gases coming out will be sum of fuel and air supplied. 

Hence, mass flow = (1 + mf ) kg/s