# Q&A - Ask Doubts and Get Answers

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Engineering
28 Views   |   1 week ago
what is the hybridisation and structure  of     ?

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S Sivani Reddy Kesara
Answered 4 days, 22 hours ago
of what?
Engineering
30 Views   |   1 week, 1 day ago
Sir please tell the answer of this question and solving method. Two particles executes S.H.M. of same amplitude and frequency along the same straight line. They pass one another when going in opposite directions, and each time their displacement is half of their amplitude. The phase difference between them is

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S sudhir
Answered 1 week, 1 day ago

Engineering
51 Views   |   1 week, 5 days ago

If an equilateral triangle, having vertex at the (2,-1), has a side along the line, x+y=2, then the area (in sq. units) of this triangle is :

• Option 1)

• Option 2)

6

• Option 3)

• Option 4)

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S solutionqc
Answered 1 week, 4 days ago
Option 1) Option 2) 6 Option 3) Option 4)
Engineering
73 Views   |   1 week, 5 days ago

If the sum of the first 15 terms of the series 3+7+14+24+37+.......is 15K, then k is equal to :

• Option 1)

126

• Option 2)

122

• Option 3)

81

• Option 4)

119

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S solutionqc
Answered 1 week, 4 days ago
Use Summation of series of natural numbers -   - wherein Sum of first n natural numbers    and   Summation of series of natural numbers -   - wherein Sum of  squares of first n natural numbers     3+7+14+24+37 ----------15K Let Tn=an2+bn+c            because difference is in A.P: [4,7,10,13-----------------] at n=1     ------(i)     n=2      -------(ii)     n=3        -------(iii)    ...
Engineering
71 Views   |   1 week, 6 days ago

Statement 1: An equation of a common tangent to the parabola  and the ellipse is

Statement 2: If the line is a common tangent to the parabola

and the ellipse then m satisfies

• Option 1)

Statement 1 is false, statement 2 is true

• Option 2)

Statement 1 is true, statement 2 is true; statement 2 is a correct explanation for statement 1

• Option 3)

Statement 1 is true, statement 2 is true; statement 2 is not a correct explanation for statement 1

• Option 4)

Statement 1 is true, statement 2 is false

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S solutionqc
Answered 1 week, 5 days ago
As we learnt in Equation of tangent - - wherein Tengent to is slope form.       Statement 1 :   Statement 2 : If is a common tangent to and ellipse From (i)     statement 2 is a correct explanation for statement 1.     Option 1) Statement 1 is false, statement 2 is true This option is incorrect. Option 2) Statement 1 is true, statement 2 is true; statement 2 is a correct...
Engineering
70 Views   |   1 week, 6 days ago

The eccentricity of an ellipse whose centre is at the origin is

If one of its directrices  is x=−4, then the equation of the normal to it at

is:

• Option 1)

• Option 2)

• Option 3)

• Option 4)

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S solutionqc
Answered 1 week, 5 days ago
As learned in concept Eccentricity - - wherein For the ellipse      and Equation of directrices - - wherein For the ellipse       we have  &  x=-4   From this we can calculate the value of a  so a=4 Now,   Hence, Equation of ellipse is- Differentiate to get the value of slope-  So slope at given point      is  Now by using the formula of normal of a equation-    normal at point    is ...
Engineering
16 Views   |   2 weeks ago

The correct order of -I effect is

• Option 1)

$-O^-> -COO^-> -C\left ( CH_{3} \right )_{3}> -CH_{3} > -D$

• Option 2)

$-O^-< -COO^-< -C\left ( CH_{3} \right )_{3}< -CH_{3} < -D$

• Option 3)

$-O^-> -COO^-> -C\left ( CH_{3} \right )_{3}> -CH_{3} < -D$

• Option 4)

$-COO^-> -O^-> -C\left ( CH_{3} \right )_{3} > -D> -CH_{3}$

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S SudhirSol
Answered 1 week, 6 days ago
As we learned   Positive inductive effect - Having less tendency to attractive   e- towards itself as compared to the Hydrogen atom - wherein    The correct order of +I effect is  D is slightly more electron releasing than H.   Option 1)       Option 2) Option 3) Option 4)
Engineering
37 Views   |   2 weeks ago

Let G be the geometric mean of two positive numbers a and b, and M be the arithmetic mean of    and

if   is 4:5 then a:b can be:

• Option 1)

• Option 2)

• Option 3)

• Option 4)

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S solutionqc
Answered 1 week, 6 days ago
As we learnt in  Arithmetic mean of two numbers (AM) - - wherein It is to be noted that the sequence a, A, b, is in AP where, a and b are the two numbers. and Geometric mean of two numbers (GM) - - wherein It is to be noted that a,G,b are in GP and a,b are two non - zero numbers.   Given G2 = ab and                                 Option 1) Option 2) Option 3) Option 4)
Engineering
97 Views   |   2 weeks ago

The sum of the first 20 terms common between the series 3+7+11+15+..... and 1+6+11+16+..... , is :

• Option 1)

4000

• Option 2)

4020

• Option 3)

4200

• Option 4)

4220

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S solutionqc
Answered 1 week, 6 days ago
Use Sum of n terms of an AP -   and Sum of n terms of an AP   - wherein first term common difference number of terms   series are 3,7,11,15,19,23,27,31.............. and 1,6,11,16,21,26,31.................... So common terms are 11,31,............                                            Option 1) 4000 Option 2) 4020 Option 3) 4200 Option 4) 4220
Engineering
65 Views   |   2 weeks ago
Find the last three digits of 17^256

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P Pankaj
Answered 2 weeks ago
@Shekhar Solution: We have 172 Now, 17256 2 128 = (17 ) 289 = (290 - 1)128 -290 - (128) (290) +1 128C 2 126(290) 12SC127(290) + 1 , where m is a positive integer. = 1000 m + (128) (290) [(127) (145) - 1] + 1 = 1000 m + (128) (290) (18414) + 1 = 1000 Cm + 683527] + 680 + 1 = 1000 [m + 683527] + 681 Thus, the last three digits of 17256 are 681
Engineering
64 Views   |   2 weeks, 1 day ago

which interval probability lies.

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H Himanshu Meshram
Answered 2 weeks, 1 day ago
@_Rakesh, Minimum value of probability of an event is  0 and maximum ia 1. Probabilty of an event or intervel lies in [0,1]
Engineering
59 Views   |   2 weeks, 1 day ago
find the general trem in the expansion of $(x^{2} - yx)^{12}$

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H Himanshu Meshram
Answered 2 weeks, 1 day ago
Engineering
57 Views   |   2 weeks, 1 day ago
Let  $f(x)=2^{10}x+1$ and $g(x)=3^{10}x+1$. If $(fog)(x)=x$ , then x is equal to :

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S Satyajeet kumar
Answered 2 weeks, 1 day ago
Engineering
78 Views   |   2 weeks, 1 day ago
sir,what is releation between  emf and p.d ,from chapter current electricity, plz explain me those releation

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A Avinash Dongre
Answered 2 weeks, 1 day ago

@Nilesh

The potential difference accross the terminals of a cell when it is not supplying any current is called e.m.f while

The voltage accross the terminals of a cell when it is supplying current to external resistance is known as Potential Difference .

When the cell is being charged

$E=V-iR$

$(E

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Engineering
74 Views   |   2 weeks, 1 day ago
Sir, I have a doubt about the question given in concept of charge conservation. Can't mass also be conserved?

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A Avinash Dongre
Answered 2 weeks, 1 day ago
@Shashank The law of conservation of mass or principle of mass conservation states that for any system closed to all transfers of matter and energy, the mass of the system must remain constant over time, as system's mass cannot change, so quantity cannot be added nor removed. Hence, the quantity of mass is conserved over time.
Engineering
69 Views   |   2 weeks, 1 day ago
I want to calculate resultant resistance  then how can calculate?

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A Avinash Dongre
Answered 2 weeks, 1 day ago

@Nilesh

Strategy for simplifying a resistor network

• Begin as far away as possible from the circuit location in question.
• Replace series or parallel resistors with their equivalent resistor.
• Continue, moving left until a single equivalent resistor represents the entire resistor network.
Engineering
68 Views   |   2 weeks, 1 day ago
plz help me to solve questions about effective resistance in both series  plz help me

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A Avinash Dongre
Answered 2 weeks, 1 day ago

@Nilesh  When resistors are connected in series, the current through each resistor is the same and

the total potential difference across all the resistors is equal to the sum of the potential differences across each resistor.

For example when resistor $R_{1} , R_{2} ,R_{3}$ are connected in sereis then

$R_{eq} = R_{1} + R_{2} + R_{3}$

1, 2,
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Engineering
79 Views   |   2 weeks, 1 day ago
The radius and mass of earth are increased by 0.5%. Which of the following statements are true at the surface of the earth? A) g will increase B)             g will decrease C)             Escape velocity will remain unchanged D)             Potential energy will remain unchanged

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V Vishwash Tetarwal
Answered 1 week, 5 days ago

$g = \frac{GM}{{R}^{2}}$

${v}_{e} = \sqrt{\frac{2GM}{R}}$

$U=\frac{-GMm}{R}$

$g\propto \frac{M}{{{R}^{2}}}$

${{v}_{e}}\propto \sqrt{\frac{M}{R}}$

$U\propto \frac{M}{R}$

after increasing by 0.5%

$M_{new} = M+(0.5/100)M=1.005M$

$R_{new} = R+(0.5/100)R=1.005R$

So If both mass and radius are increased by 0.5% then $v_{e}$ and U remains unchanged where as g will be decreased.

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Engineering
76 Views   |   2 weeks, 1 day ago
Hello   When a body is earth connected then the electrons from the earth flow into the body...that means the body is uncharged right?? When the body is earth connected , how can the body be positively charged? Like I meant the electrons doesn't flow as it remains unchanged Hello anybody there   Plzz reply

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V Vishwash Tetarwal
Answered 1 week, 5 days ago

the body is positively charged before grounding and after that electrons flows from earth to body and body becomes neutral.

the Body is positively charged before grounding because If a body is grounded and electrons starts flowing into the body from then Earth this would mean that the charges inside the body are attracting the negative electrons from Earth as a potential difference is being developed at the two ends, the Earth and the body.

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Engineering
1 Views   |   2 weeks, 1 day ago
Hello   When a body is earth connected then the electrons from the earth flow into the body...that means the body is uncharged right?? When the body is earth connected , how can the body be positively charged? Like I meant the electrons doesn't flow as it remains unchanged Hello anybody there   Plzz reply
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