Tags Class 12th

Class 12th

Get insights from 12k questions on Class 12th, answered by students, alumni, and experts. You may also ask and answer any question you like about Class 12th

Follow Ask Question

12k

Questions

Discussions

Active Users

Followers

New answer posted

6 months ago

Class 12th Chemistry

When 200mL of 0.2 M acetic acid is shaken with 0.6g of wood charcoal, the final concentration of acetic acid after adsorption is 0.1M. The mass of acetic acid adsorbed per gram of carbon is ______________ g.

0 Follower 5 Views

Payal Gupta

Contributor-Level 10

Number of moles of CH₃COOH Adsorbed on 0.6 gm wood charcoal.

$= (0.2 * 200) * 1 0^{- 3} - (0.1 * 200) * 1 0^{- 3}$

= 20 * 10^-3 moles

Mass of CH₃COOH absorbed = 20 * 10^-3 * 60 = 1.2 gm

Mass of CH₃COOH adsorbed per gram = $\frac{1.2}{0.6} = 2 g$ of charcoal.

0 0

New answer posted

6 months ago

Class 12th Chemistry Electrochemistry

The resistance of a conductivity cell containing 0.01 MKCl solution at 298K is $1750 Ω$ . If is 0.152 * 10^-3 cm^-1, then the cell constant of the conductivity cell _________ * 10^-3 cm^-1.

0 Follower 2 Views

Payal Gupta

Contributor-Level 10

$K = \frac{1}{R} * c e l l c o n s t a n t$

= 0.152 * 10^-3 * 1750

= 266 * 10^-3 cm^-1

0 0

New answer posted

6 months ago

Class 12th Chemistry Solutions

A Company dissolves 'x' amount of CO₂ at 298K in 1 litre of water to prepare soda water X = _________________ * 10^-3 g. (nearest integer)

0 Follower 4 Views

Payal Gupta

Contributor-Level 10

According to Henry's law

$P_{G a s} = K_{H} * x_{G a s}$

$= 0.835 = 1.67 * 1 0^{3} * [\frac{n_{C O_{2}}}{n_{C O_{2}} + 55.5}]$

As $n_{C O_{2}} < < 55.5$

$\Rightarrow n_{C O_{2}} = 27.78 * 1 0^{- 3} m o l e s$

Mass of CO₂ gas = $n_{C O_{2}} * (M M) C O_{2}$

= 1222 * 10^-3gm

0 0

New answer posted

6 months ago

Class 12th Maths

The number of values of a for which the system of equations :

x + y + z = a

ax + 2ay + 3z = -1

x + 3ay + 5z = 4

is inconsistent, is

0 Follower 6 Views

alok kumar singh

Contributor-Level 10

For inconsistent, $Δ = 0, | \begin{matrix} 1 & 1 & 1 \\ α & 2 a & 3 \\ 1 & 3 α & 5 \end{matrix} | = 0$

a = 1

$∴ Δ_{1} = | \begin{matrix} 1 & 1 & 1 \\ - 1 & 2 & 3 \\ 4 & 3 & 5 \end{matrix} | = 1 (1) + 1 (12 + 5) + 1 (- 3 - 8) = 7 \neq 0$

0 0

New answer posted

6 months ago

Class 12th Maths

Bag A contains 2 white, 1 black and 3 red balls and bag B contains 3 black, 2 red and n white balls. One bag is chosen at random and 2 balls drawn from it at random are found to be 1 red and 1 black. If the probability that both balls come from Bag A is $\frac{6}{11},$ then n is equal to ________.

0 Follower 1 View

alok kumar singh

Contributor-Level 10

$\frac{6}{11}$ = Required probability

After solving, we get n = 4

0 0

New answer posted

6 months ago

Class 12th Maths

The surface area of a balloon of spherical shape being inflated increases at a constant rate. If initially, the radius of balloon is 3 units and after 5 seconds, it becomes 7 units, then its radius after 9 seconds is :

0 Follower 4 Views

alok kumar singh

Contributor-Level 10

Surface area, S = 4pr²

$? \frac{d s}{d t} = 4 ? . 2 r \frac{d r}{d t} = 8 ? \frac{d r}{d t} = c o n s t a n t = k (s a y)$

$? \frac{d s}{d t} = k ? s = k t + c$

$? 4 ? r^{2} = k t + c$

Initially t = 0, r = 3

c = 36 p

When t = 5, r = 7, k = 32p

When t = 9, r = r, r = 9

0 0

New answer posted

6 months ago

Class 12th Maths

In an examination, there are 1- true-false type questions. Out of 10, at student can guess the answer of 4 questions correctly with probability $\frac{3}{4}$ and the remaining 6 questions correctly with probability $\frac{1}{4}$ . If the probability that the student guesses the answer of exactly 8 questions correctly out of 10 is $\frac{27 k}{4^{10}},$ then k is equal to

0 Follower 2 Views

Payal Gupta

Contributor-Level 10

Since student guesses only two wrong. So there are three possibilities

(i) both wrong in section A

(ii) both wrong in section B

(iii) one wrong in each section A and B.

$∴$ Required possibilities =

$=^{4} C_{4} *^{6} C_{4} {(\frac{3}{4})}^{4} * {(\frac{1}{4})}^{4} {(\frac{3}{4})}^{2} +^{4} C_{3} *^{6} C_{5} {(\frac{3}{4})}^{3} {(\frac{1}{4})}^{5} * \frac{1}{4} * \frac{3}{4}$ $+^{4} C_{2} *^{6} C_{6} * {(\frac{3}{4})}^{2} {(\frac{1}{4})}^{2} * {(\frac{1}{4})}^{6}$

$= \frac{27}{4^{10}} [15 * 27 + 24 * 3 + 2] = \frac{27 * 479}{4^{10}}$

0 0

New answer posted

6 months ago

Class 12th Maths

Let S = ${z \in C : | z - 3 | \leq 1 a n d z (4 + 3 i) \leq 24} .$ If $α + i β$ is the point in S which in closest to 4i, then 25 $(α + β)$ is equal to

0 Follower 10 Views

Payal Gupta

Contributor-Level 10

Circle $| z - 3 | \leq 1 \Rightarrow {(x - 3)}^{2} + y^{2} \leq 1$

and line $z (4 + 3 i) + \bar{z} (4 - 3 i) \leq 24$

$\Rightarrow 4 x - 3 y \leq 12 ∴ s l o p e = t a n θ = \frac{4}{3}$

0 0

New answer posted

6 months ago

Class 12th Maths

Let $λ$ be the largest value of $λ$ for which the function $f_{λ} (x) = 4 λ x^{3} - 36 λ x^{2} + 36 x + 48$ is increasing for all $x \in R .$ Then $f_{λ} . (1) + f_{λ} . (- 1)$ is equal to

0 Follower 2 Views

Payal Gupta

Contributor-Level 10

$? f_{λ} (x) = 4 λ x^{3} - 36 λ x^{2} + 36 x + 48$

$f_{λ} (x) = 12 (λ x^{2} - 6 λ x + 3)$

For increasing $f_{λ} (x) \geq 0$

$f_{λ}^{*} (x) = \frac{4}{3} x^{3} - 12 x^{2} + 36 x + 48 ∴ f_{λ}^{*} (1) + f_{λ}^{*} (- 1) = 73 \frac{1}{2} - 1 \frac{1}{2} = 72$

0 0

New answer posted

6 months ago

Class 12th Maths

The slope of normal at any point (x,y), X > 0, y > 0 on the curve y = y(x) is given by $\frac{x^{2}}{x y - x^{2} y^{2} - 1} .$ If the curve passes through the point (1, 1), then e.y (e) is equal to

0 Follower 6 Views

Payal Gupta

Contributor-Level 10

$? - \frac{d x}{d y} = \frac{x^{2}}{x y - x^{2} y^{2} - 1}$

$∴ \frac{d y}{d x} = \frac{x y - x^{2} y^{2} - 1}{x^{2}}$

$L e t x y = v \Rightarrow x \frac{d y}{d x} + y = \frac{d v}{d x}$

Put x = 1, y = 1 $\Rightarrow t a n^{- 1} = c \Rightarrow c = \frac{π}{4}$

$∴ t a n^{- 1} (x y) = l n x = \frac{π}{4}$

$e (y (e)) = t a n (1 + \frac{π}{4}) = \frac{t a n 1 + 1}{1 - t a n 1}$

0 0

Get authentic answers from experts, students and alumni that you won't find anywhere else

On Shiksha, get access to

66k Colleges
1.2k Exams
681k Reviews
1800k Answers

Community GuidelinesUser Points System

QuestionsDiscussionsTags

Need guidance on career and education? Ask our experts

Your Question

Class 12th

Questions

Discussions

Active Users

Followers

All

Discussions

Unanswered Questions

Share Your College Life Experience