Recent questions tagged medium

Sodium amalgam is used as

asked Jan 28, 2014 by sreemathi.v

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What is the resistivity of n-type semiconductors given: Density of conducting electrons $=8 \times 10^{13} /cc$; Density of holes $=5 \times 10^{12} /cc$ mobility of electron $=2.3 \times 10^4 cm^2 /v-s$ mobility of holes $=100 cm^2 /v-s$

asked Jan 28, 2014 by meena.p

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Find the current through resistance in the circuit.

asked Jan 28, 2014 by meena.p

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In the given diagram resistance of each diode in forward bias is zero and infinity in reverse bias . If a 2V battery is connected as shown in circuit What is the effective current.

asked Jan 27, 2014 by meena.p

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If $\ast$ is a binary operation on the set $(\{0, 1, 2, 3, 4, 5\})$ defined as \[ a \ast b = \left\{ \begin{array} {1 1} a+b, & \quad \text{ if a$+$b $<$ 6} \\ a+b-6, & \quad \text{ if a+b $\geq$ 6} \\ \end{array} \right. \] then draw the composition table for the operation and find the identity element and inverse of $4$ if exists.

asked Jan 27, 2014 by rvidyagovindarajan_1

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When a 10v battery is connected as shown in the circuit what is the potential difference across A and B ?

asked Jan 27, 2014 by meena.p

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If the slopes of the line of regression of $y$ on $x$ and of $x$ on $y$ are $30^{\circ}$ and $60^{\circ}$ respectively. Then $ r(x,y)$ is

asked Jan 27, 2014 by thanvigandhi_1

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The diode connected in forward bias has zero resistance and if connected in reverse biase has infinity resistance Find the effective resistance across A and B the given circuit.

asked Jan 27, 2014 by meena.p

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If the SD of X is $\sigma_X$ then SD of $\large\frac{aX-b}{c}$ ( where a,b,c are constants ) is:

asked Jan 27, 2014 by thanvigandhi_1

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Alkali metals are

asked Jan 27, 2014 by sreemathi.v

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The correlation between $x$ and $a-x$ is

asked Jan 27, 2014 by thanvigandhi_1

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Which of the following does not give metal oxide on heating

asked Jan 27, 2014 by sreemathi.v

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For $a$ series the value of mean deviation is 15. The most likely value of its quartile deviation is

asked Jan 27, 2014 by thanvigandhi_1

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What is current and voltage across the diode in The given circuit given drift current is $ 2 \times 10^{-3}A$

asked Jan 27, 2014 by meena.p

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unpaired electrons $(e^-)$ are present in

asked Jan 27, 2014 by sreemathi.v

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Tetra ethyl lead is prepared by using an alloy

asked Jan 27, 2014 by sreemathi.v

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In Germanium it is found that concentration of conducting electron is $3 \times 10^{19} $ per cubic meter. When Phosphorus impurity is doped the concentration of conducting electron increases to $2 \times 10^{23}$ per cubic meter. If product of hole concentration and conducting electron is independent of amount of impurity find the hole concentration in doped Germanium.

asked Jan 27, 2014 by meena.p

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The ashes of plants contain alkali-metals and 90% of which is

asked Jan 27, 2014 by sreemathi.v

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In the given circuit, potential barriers developed across diode is $0.5 v$ . Find the current in the circuit.

asked Jan 27, 2014 by meena.p

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Metal used in the detection of nitrogen in organic compound is

asked Jan 27, 2014 by sreemathi.v

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The ratio of volume of the hydrogen liberated at S.T.P when equal amounts of tin reacts with dilute NaOH and conc NaOH.

asked Jan 27, 2014 by sreemathi.v

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Which of the following is the correct order of chemical reactivity with water according to electrochemical series?

asked Jan 27, 2014 by sreemathi.v

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The least basic oxide is

asked Jan 27, 2014 by sreemathi.v

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Which one is highest melting point halide

asked Jan 27, 2014 by sreemathi.v

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A mixture of $Al(OH)_3$ and $Fe(OH)_3$ can be separated by

asked Jan 27, 2014 by sreemathi.v

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Which of the following salts does not form any precipitate with excess of $NaOH$?

asked Jan 27, 2014 by sreemathi.v

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Which of the following alkali metals has the highest tendency for the half reaction? $M(g)\rightarrow M^+(g)+e^-$

asked Jan 27, 2014 by sreemathi.v

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In a p-n junction the depletion region is $200 nm$ wide and a electric field of $10^6 vm^{-1}$ exists in it. What is the minimum kinetic energy of conducting electron to diffuse through the barriers.

asked Jan 27, 2014 by meena.p

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In pure semiconductor number of conducting electrons is $5 \times 10^{20} $ per cubic meter. How many holes are there in $1 cm^3$ of the same semiconductor.

asked Jan 27, 2014 by meena.p

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Which of the following are incorrect statements about a transistor?

asked Jan 27, 2014 by meena.p

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The quartile deviation for the data : \[\] x : 2 3 4 5 6 \[\] f : 3 4 8 4 1

asked Jan 26, 2014 by thanvigandhi_1

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The A.M of set of 50 numbers is 48. If two numbers 52 and 44 are discarded then A.M of the remaining set of numbers is

asked Jan 25, 2014 by thanvigandhi_1

1 answer

The S.D of first $n$ naturals is

asked Jan 25, 2014 by thanvigandhi_1

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The weighted mean of first $n$ natural numbers whose weights are equal to the squares of the corresponding numbers is

asked Jan 25, 2014 by thanvigandhi_1

1 answer

If the mean of the set of numbers $ x_1, x_2.....x_n$ is $ \overline x$ then mean of the numbers $ x_i+2i \: \: 1 \leq i \leq n $ is

asked Jan 25, 2014 by thanvigandhi_1

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If a student gets marks : English 80, Hindi 70, Mathematics 85, Physics 75 and Chemistry 67 and the weights of subjects are 1,2,1,3,1 respectively then weighted A.M is

asked Jan 25, 2014 by thanvigandhi_1

1 answer

The A.M of 9 items is 15. If one more item is added to this series, the A.M becomes 16. The value of 10th item is

asked Jan 25, 2014 by thanvigandhi_1

1 answer

If A.M of $x_1, x_2....x_n$ is $ \overline x$ then A.M of $ ax_1+b, ax_2+b, ax_3+b...ax_4+b$ is

asked Jan 25, 2014 by thanvigandhi_1

1 answer

The A.M of first $n$ natural number is

asked Jan 25, 2014 by thanvigandhi_1

1 answer

A batsman scores $ 38, 70, 48, 34, 42, 55, 63, 46, 54 \: and \: 44$ in 10 innings. Find his mean deviation from median.

asked Jan 25, 2014 by thanvigandhi_1

1 answer

Two waves have a phase difference of $\pi $. and they have light intensities I and 9I. What will be the resultant intensity .

asked Jan 24, 2014 by meena.p

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Find the width of central maxima given $\lambda = 5 \times 10^{-5}\;cm$ slit separation $d= 0.15 \;cm$ and distance between screen and slit $D= 2.1 \;m$

asked Jan 24, 2014 by meena.p

1 answer

An unpolarised light is incident on a glass plate at polarizing angle $57^{\circ}$ with the normal on a glass plane. The reflected light will be

asked Jan 24, 2014 by meena.p

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If the electron energy is -3.4 eV , Find the principal quantum number of H-atom?

asked Jan 24, 2014 by sharmaaparna1

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The velocity of an electron in a certain Bohr's orbit of H-atom bears the ratio 1:275 to the velocity of light. Then find the quantum numbers (n) of orbit.

asked Jan 24, 2014 by sharmaaparna1

1 answer

Hyperol is an addition product of $H_2O_2$ with

asked Jan 24, 2014 by sreemathi.v

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The gas liberated when alkaline formaldehyde solution is reacted with hydrogen peroxide in the presence of pyragahol is

asked Jan 24, 2014 by sreemathi.v

1 answer

In a young's double slit experiment illuminated by monochromatic light the slit separation is $0.3\;mm$ and slit- screen separation is $1.5 \;m$. If fourth bright fringe is 1 cm from central bright fringe, the wavelength of light used is

asked Jan 24, 2014 by meena.p

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What is the oxidation state of Fe in the product formed when acidified pottasium ferrocyanide treated with $H_2O_2$?

asked Jan 24, 2014 by sreemathi.v

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If the speed of sound in Hydrogen at NTP is equal to the speed of sound in carbon-di-oxide at $T_0$, what is the value of $T_0$? (i.e, $T = 273K$)

asked Jan 24, 2014 by balaji.thirumalai

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