Recent questions tagged 67

A hollow metal sphere of radius R is uniformly charged. The electric field due to the sphere at a distance r from the centre :

asked Jul 8, 2019 by pady_1

1 answer

An organic compound having carbon and hydrogen has $80\%$ carbon. The empirical formula of the hydrocarbon is :

asked Dec 19, 2018 by pady_1

0 answers

At what temperature the density of heavy water will be maximum ?

asked Dec 19, 2018 by pady_1

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Chloroethane reacts with magnesium in dry ether to form $X$. When $X$ is hydrolysed a carbon compound $Y$ and $Z$ are formed. Which of the following is $Y$?

asked Dec 19, 2018 by pady_1

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The structural formula 2-methyl-2-butene is :

asked Dec 11, 2018 by pady_1

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Two spheres of the same material have radii $1m$ and $4m$ and temperatures $4000 K$ and $2000 K$ respectively. The ratio of the energy radiated per second by the first sphere to that by the second is :

asked Dec 11, 2018 by pady_1

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A rocket with a lift-off mass $3.5 \times 10^4 kg$ is blasted upwards with an initial acceleration of $10 m/s^2$. Then the initial thrust of the blast is :

asked Dec 11, 2018 by pady_1

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The ratio of mass percent of $C$ and $H$ of an organic compound $(C_XH_YO_Z)$ is $6:1$. If one molecule of the above compound $(C_XH_YO_Z)$ contains half as much oxygen as required to burn one molecule of compound $C_XH_Y$ completely to $CO_2$ and $H_2O$. The empirical formula of compound $C_XH_YO_Z$ is :

asked Dec 11, 2018 by pady_1

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Given : $E^{\circ}_{Cl_2/Cl^-} = 136 \; V, \; \; \; E^{\circ}_{Cr^{3+} / Cr} = -0.74 \; V$ $E^{\circ}_{Cr_2O_7^{2-}/Cr^{3+}} = 1.33\; V, \; \; \; E^{\circ}_{MnO_4^- / Mn^{2+}} = 1.51 \; V$ Among the following, the strongest reducing agent is :

asked Dec 11, 2018 by pady_1

0 answers

If the number of terms in the expansion of $\begin{pmatrix} 1 - \frac{2}{x} + \frac{4}{x^2} \end{pmatrix}^n, x \neq 0$ is 28, then the sum of the coefficients of all the terms in this expansion, is :

asked Dec 11, 2018 by pady_1

1 answer

Let the sum of the first three terms of an A.P. be 39 and the sum of its last four terms be 178. If the first term of this A.P. is 10, then the median of the A.P. is :

asked Dec 11, 2018 by pady_1

1 answer

In which of the following reactions $H_2O_2$ acts as a reducing agent? (a) $H_2O_2 +2H^+ + 2e^- \to 2H_2O$ (b) $H_2O_2 - 2e^- \to O_2 + 2H^+$ (c) $H_2O_2 + 2e^- \to 2OH^- $ (d) $H_2O_2 + 2OH^- - 2e^- \to O_2 + 2H_2O$

asked Dec 11, 2018 by pady_1

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The anode voltage of a photocell is kept fixed. The wavelength $\lambda$ of the light falling on the cathode is gradually changed. The plate current I of the photocell varies as follows:

asked Dec 11, 2018 by pady_1

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The density of a solution prepared by dissolving 120 g of urea ( mol. Mass = 60 u) in 1000 g of water is 1.15 g/mL. The molarity of this solution is :

asked Dec 11, 2018 by pady_1

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The degree of dissociation $(\alpha$) of a weak electrolyte $A_xB_y$ is related to vant Hoff factor (i) by the expression :

asked Dec 11, 2018 by pady_1

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If two tangets drawn from a point P to the parabola $y^2 = 4x$ are at right angles, then the locus of P is

asked Dec 11, 2018 by pady_1

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If $\overrightarrow{u}, \overrightarrow{v}, \overrightarrow{w}$ are non-coplanar vectors and $p, q$ are real numbers, then the equality $[3\overrightarrow{u} \;\; p\overrightarrow{v} \;\; p\overrightarrow{w}] - [p \overrightarrow{v} \;\; \overrightarrow{w}\; \; q \overrightarrow{u}] - [2 \overrightarrow{w}\; \; q \overrightarrow{v}\;\;q \overrightarrow{u}] = 0$ holds for

asked Nov 29, 2018 by pady_1

0 answers

The hydrocarbon which can react with sodium in liquid ammonia is

asked Nov 29, 2018 by pady_1

0 answers

A charged particle moves through a magnetic field perpendicular to its direction. Then :

asked Nov 29, 2018 by pady_1

0 answers

In the transformation of $_{92}^{238}U$ to $_{92}^{234}U$, if one emission is an $\alpha$-particle, what should be the other emission (s) ?

asked Nov 13, 2018 by pady_1

0 answers

Let $x_1, x_2 , . . . . x_n$ be $n$ observation such that $ \Sigma x_i^2 = 400 $ and $ \Sigma x_i = 80$. Then a possible value of $n$ among the following is :

asked Nov 5, 2018 by pady_1

0 answers

The self-inductance of the motor of an electric fan is 10 H. In order to impart maximum power at 50 Hz, it should be connected to a capacitance of :

asked Nov 5, 2018 by pady_1

0 answers

The probability that A speaks truth is $\frac{4}{5}$, while this probability for B is $\frac{3}{4}$. The probability that they contradict each other when asked to speak on a fact is

asked Nov 5, 2018 by pady_1

0 answers

Magnesium reacts with an element (X) to form an ionic compoun. If the ground state electronic configuration of (X) is $1s^2 2s^2 2p^3$, the simplest formula for this compound is

asked Aug 21, 2018 by pady_1

1 answer

Which of the following options best represents the enzyme composition of pancreatic juice ?

asked Aug 21, 2018 by pady_1

1 answer

Seed formation without fertilization in following plants involves the process of

asked Aug 21, 2018 by pady_1

1 answer

In which group of organisms the cell walls form two thin overlapping shells which fit together?

asked Aug 21, 2018 by pady_1

1 answer

Acidity of diprotic acids in aqueous solutions increases in the order:

asked Aug 20, 2018 by pady_1

1 answer

Which of the following lanthanoid ions is diamagnetic ? (At. No. Ce = 58, Sm = 62, Eu = 63, Yb = 70)

asked Aug 20, 2018 by pady_1

0 answers

The number of octahedral void(s) per atom present in a cubic close-packed structure is :

asked Aug 20, 2018 by pady_1

1 answer

Standard electrode potential of three metals X, Y and Z are –1.2 V, + 0.5 V and –3.0 V respectively. The reducing power of these metals will be :

asked Aug 16, 2018 by pady_1

1 answer

Which of the following ions will exhibit colour in aqueous solutions?

asked Jul 26, 2018 by pady_1

1 answer

The values of $\Delta H$and $\Delta S$ for the reaction, $C(graphite)+CO_2(g)\rightarrow 2CO(g)$ are 170 kJ and $170 JK^{–1} $respectively. This reaction will be spontaneous at -

asked Jul 26, 2018 by pady_1

2 answers

Which one of the following is most reactive towards electrophilic attack ?

asked Jul 26, 2018 by pady_1

1 answer

A weak acid HA has a $K_a$ of $1.00 \times 10^{-5}$. If $0.100\; mol $ of this acid is dissolved in one litre of water the percentage of acid dissociated at equilibrium is closest to :

asked Jul 26, 2018 by pady_1

0 answers

If $E^{\circ}_{Fe^{2+}/Fe}=-0.441V$ and $E^{\circ}_{Fe^{3+}/Fe^{2+}}=-0.771V$, the standard EMF of the reaction : ${Fe/2Fe^{3+}}\to 3Fe^{2+}$ will be:

asked Jul 25, 2018 by pady_1

0 answers

A solution of urea (mol. mass $56\;g\;mol^{-1}$) boils at $100.18^{\circ}C$ at the atomospheric pressure. If $K_f$ and $K_b$ for water are $1.86$ and $0.512\;K g\;mol^{-1}$ respectively , the above solution will freeze at :-

asked Jul 24, 2018 by pady_1

1 answer

Camphor is often used in molecular mass determination because :-

asked Jul 24, 2018 by pady_1

1 answer

The solubility product of AgI at $25^oC$ is $1.0 \times 10^{–16} mol^2 L^{–2}$. The solubility of AgI in $10^{–4} N$ solution of KI at $25^oC$ is approximately (in $mol\; L^{–1}$) :

asked Jul 24, 2018 by pady_1

1 answer

A solution containing components A and B follows Raoult's law : -

asked Jul 23, 2018 by pady_1

1 answer

A compound of molecular formula is $C_7H_{16}$ shows optical isomerism, compound will be

asked Jul 20, 2018 by pady_1

1 answer

Equilibrium constant Kp for following reaction : $MgCO_3(s)\rightleftharpoons MgO(s)+CO_2(g)$

asked Jul 20, 2018 by pady_1

1 answer

The number of antibonding electron pair in $O{_2}^{-2}$ is :

asked Jun 15, 2018 by pady_1

1 answer

WORK : MOTIVE ::

asked Dec 31, 2015 by pady_1

1 answer

Type the missing number in this sequence: 3, 6, 12, 24, ------ , 96

asked Dec 31, 2015 by pady_1

1 answer

A bakery is 8 metres wide and 15 metres long. The baker wants to put a wooden shelf around the inside of the bakery. The wooden shelving costs Rs 1,455.00 per metre. How much will the baker's shelf cost?

asked Dec 31, 2015 by pady_1

1 answer

There are 38 students in class 8. There are 13 boys in the class. What is the fraction of girls in the class ?

asked Dec 31, 2015 by pady_1

0 answers

A shopkeeper buys a football for \$ 150 and sells it at \$ 210. What is his profit or loss?

asked Dec 31, 2015 by pady_1

0 answers

The figure represents

asked Jan 30, 2014 by meena.p

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