Class 12th

A uniform wire of resistance $20 Ω$ having resistance $1 Ω / m$ is bent in the form of a circle as shown in figure. If the equivalent resistance between $A$ and $B$ is $1.8 Ω$ , then length of the shorter section is

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alok kumar singh

Contributor-Level 10

Resistance of whole wire is

$R = r^{'} * l$

$20 = 1 * l$

$l = 20 m$

Let length of the shorter section = a

$\frac{1}{R} = \frac{1}{a} + \frac{1}{(20 - a)}$

$\frac{1}{1.8} = \frac{20 - a + a}{a (20 - a)} ? 20 a - a^{2} = 36$

$a = 2 a n d 18$

$? a = 2 m$

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New answer posted

a year ago

Statement – I : Ellingham diagram explains the kinetics of reduction process.

Statement – II : Hydraulic washing, a method of concentration of ore is based on the differences in gravities of the ore and the gangue.

In the light of above statements choose the correct option among the following.

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Contributor-Level 10

Ellingham diagram explains the feasibility of reduction process not the kinetics of process.

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New answer posted

a year ago

What is the difference between inductance and resistance?

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Aadit Singh Uppal

Contributor-Level 10

While both of them oppose the flow of electric current, the key difference lies in their energy output. In the case of resistance, energy is released in the form of heat. On the other hand, inductance stores energy in its magnetic field and doesn't waste it.

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New answer posted

a year ago

The phenomenon of producing electrical signals in a crystal by applying pressure is known as

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Contributor-Level 10

Electricity produced by applying pressure on a crystal is known as piezoelectricity.

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New answer posted

a year ago

Choose the correct statement for the circuit shown in figure

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alok kumar singh

Contributor-Level 10

(Explanation can be elaborate)

l = \frac{25}{R_{e q}}

R_{e q} = 25 Ω

l = \frac{25}{25} 1 A

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New answer posted

a year ago

Statement – I : hcp and ccp structure are equally efficient.

Statement – II : Same number of atoms are present in a hcp and ccp unit cell.

In the light of above statement choose the correct option among the following.

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Class 12th Chemistry Electrochemistry

Contributor-Level 10

Packing efficiency for both ccp and hcp structures are 74%

Z_ccp= Z_FCC = 4

Z_HCP = 6

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New answer posted

a year ago

The $E_{c e l l}^{0}$ for the cell reaction

$C r + F e^{2 +} \to C r^{3 +} + F e$ , will be (Given: $? G^{0} = - 170 k J m o l^{- 1})$

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Contributor-Level 10

$2 C r + 3 F e^{2 +} \overset{n = 6}{\to} 2 C r^{3 +} + 3 F e$

$? G^{0} = - n E^{0} F$

$170 * 10^{3} = - 6 * E^{0} * 96500$

$E_{c e l l}^{0} = 0.29 V$

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New answer posted

a year ago

For a region of constant electric potential, which of the following statements is incorrect?

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alok kumar singh

Contributor-Level 10

(Explanation can be elaborate)

For a region of constant electric potential

(1) The electric field may be uniform

(2) The electric field may be zero

(3) There can be no charge inside the region

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New answer posted

a year ago

Correct IUPAC name of the following compounds is

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