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Class 12th Maths

If f(x) = $[\begin{matrix} \frac{1}{| x |} & a x^{2} + b \end{matrix} \begin{matrix} | x | \geq 1 & | x | < 1 \end{matrix},$ is differentiable everywhere and K = a + b, then value of k is

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Vishal Baghel

Contributor-Level 10

$f (x) = [\begin{array}{l} - \frac{1}{x} x \in (- \infty, - 1) \\ a x^{2} + b x \in (- 1, 1) \\ \frac{1}{x} x \in [1, \infty) \end{array}$

cont at x = 1, a + b = 1

diff at x = 1, 2a = 1 $\Rightarrow a = - \frac{1}{2} \Rightarrow b = \frac{3}{2}$

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Class 12th Maths

Value of $\int_{- π / 2}^{π / 2} \frac{d x}{(1 + t a n^{2} x) (1 + 2^{x})}$ equals

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Vishal Baghel

Contributor-Level 10

$\int_{0}^{π / 2} (\frac{1}{(1 + t a n^{2} x) (1 + 2^{x})} + \frac{1}{(1 + t a n^{2} x) (1 + 2^{- x})}) d x$

$\int_{0}^{π / 2} \frac{d x}{(1 + t a n^{2} x)} = \int_{0}^{π / 2} c o s^{2} x d x = \frac{π}{4}$

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Class 12th Chemistry

How many hydrogen atom(s) is/are present in precipitate (P)?

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Vishal Baghel

Contributor-Level 10

Kindly consider the following figure

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Class 12th Chemistry Electrochemistry

A thin circular-disk earrings 10.0cm in diameter is plated with a coating of gold 0.20mm thick from an Au³⁺ bath. How many days (approx.) does it take to deposit the gold on one side of one earring if the current is 0.193 ampere.

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Vishal Baghel

Contributor-Level 10

Eq. = no. of faraday

$\frac{10 * 0.2 * 1 0^{- 2} * 19.7}{197} * 3 = \frac{0.193 * t}{96500}$

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6 months ago

Class 12th Chemistry

A metal crystallises as simple cubic crystal. The distance between the nearest neighbours of each atom is $\frac{258.36}{\sqrt[]{2}} p m .$ The atomic radius of metal atoms (in pm) is

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Vishal Baghel

Contributor-Level 10

$\sqrt[]{2} a = \frac{258.36}{\sqrt[]{2}}$

$α = 258.36 = 2 r$

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6 months ago

Class 12th Chemistry

How many H-atome can be exchanged by D-atom when the following compound is kept in $\overset{Θ}{O} D / D_{2} O$ solution for long time?

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Vishal Baghel

Contributor-Level 10

Kindly go through the answers

(8.00)

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Class 12th Chemistry Chemical Kinetics

The decomposition of hydrogen peroxide follows first order kinetics.

2H₂O₂(aq) $\overset{}{\to}$ 2H₂O $(l)$ + O₂(g)

If the volume of O₂ gas liberated at S TP in first 2- minutes of the start of decomposition is 25.00ml, what should be the total volume of O₂ gas (in ml) collected in time, t >> T_1/2. (t_1/2 for the decomposition of H₂O₂ is 10 min)

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Vishal Baghel

Contributor-Level 10

$\begin{array}{l} t = \frac{t_{1 / 2}}{l o g 2} . l o g \frac{V_{\infty}}{V_{\infty} - V_{t}} \\ 20 = \frac{10}{l o g 2} . l o g \frac{V_{\infty}}{V_{\infty} - 25} \end{array}$

$∴ V_{\infty} = 33.33 m l$

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6 months ago

Class 12th Physics Semiconductor Devices

In “Al” and “Si”, if temperature is changed from normal temperature to 70 K then

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Raj Pandey

Contributor-Level 9

$T ↓ (300 Kto 70 K)$

$\begin{array}{l} T ↓ R_{meta 1} ↓ R ↑ \\ (A l) (Si) \end{array}$ semi? conductor

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Class 12th Physics

Two balls of same mass and carrying equal charge are hung by threads of length $l$ from a fixed support. At electrostatic equilibrium, assuming that angles made by each thread is small, the separation, $x$ between the balls is proportional to: