Recent questions tagged 35

For the cell reaction $2Fe^{3+}(aq)+2I^{-}(aq)\rightarrow2Fe^{2+}(aq)+I_2(aq)$ $E^{\ominus}_{cell}$ cell E 0.24V at 298 K. The standard Gibbs energy $(\triangle^{\circ}_{r}G^{\ominus})$of the cell reaction is : [Given that Faraday constant $F = 96500 C \;mol^{-1}$

asked Jul 8, 2019 by pady_1

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The charges $+ 5 \; \mu C$ and $+ 10 \; \mu C$ are placed $20\; cm$ apart. The electric field at the mid point between the two charges is :

asked Dec 19, 2018 by pady_1

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In a spectrometer experiment three prisms $A,\;B$ and $C$ with same angle of prism but of different materials of refractive indices $\mu_A = 1.33, \; \mu_B = 1.55, \; \mu_C = 1.44$ are used. The corresponding angles of minimum deviation $D_A,\;D_B,\;D_C$ measured will be such that :

asked Dec 19, 2018 by pady_1

1 answer

The height of the point vertically above the earth's surface at which acceleration due to gravity becomes 1% of its value at the surface is : (Radius of the earth = R)

asked Dec 19, 2018 by pady_1

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An object is projeced with a velocity of $20\;m/s$ making an angle of $45^{\circ}$ with horizontal. The equation for the trajectory is $"h = Ax - Bx^2"$ where $'h'$ is height, $'x'$ is horizontal distance A and B are constats. The ratio $A : B$ is : $(g = 10\;m/s^2)$

asked Dec 11, 2018 by pady_1

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Which of the following is more close to a black body ?

asked Dec 11, 2018 by pady_1

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A mass M is suspended from a spring of negligible mass. The spring is pulled a little and then released so that the mass executes SHM of time period T. If the mass is increased by $m$, the time period becomes $5T/3$, then the ratio of $\frac{m}{M}$ is :

asked Dec 11, 2018 by pady_1

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If the curves $y^2 = 6x, \; 9x^2 + by^2=16$ intersect each other at right angles, then the value of $b$ is :

asked Dec 11, 2018 by pady_1

1 answer

A slender uniform rod of mass M and length l is pivoted at one end so that it can rotate in a vertical plane (see figure). There is negligible friction at the pivot. The free end is held vertically above the pivot and then released. the angular acceleration of the rod when it makes an angle $\theta$ with the vertical is

asked Dec 11, 2018 by pady_1

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The heats of combustion of carbon and carbon monoxide are $−393.5$ and $−283.5\; kJ \;mol^{−1}$ , respectively. The heat of formation (in kJ) of carbon monoxide per mole is :

asked Dec 11, 2018 by pady_1

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The heat of atomization of methane and ethane are $360\; kJ/mol$ and $620\; kJ/mol$, respectively. The longest wavelength of light capable of breaking the $C - C$ bond is (Avogadro number =$ 6.02 \times 10^{23} ,\; h =6.62 \times 10^{-34}\; J s$) :

asked Dec 11, 2018 by pady_1

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The variance of first 50 even natural numbers is

asked Dec 11, 2018 by pady_1

1 answer

All the students of a class performed poorly in Mathematics. The teacher decided to give grace marks of 10 to each of the students. Which of the following statistical measures will not change even after the grace marks were given ?

asked Dec 11, 2018 by pady_1

1 answer

If a simple pendulum has significant amplitude (up to a factor of 1/e of original) only in the period between $t = Os$ to $ t = \tau s$, then $\tau$ may be called the average life of the pendulum. When the spherical bob of the pendulum suffers a retardation (due to viscous drag) proportional to its velocity, with 'b' as the constant of proportionality, the average life time of the pendulum is ( assuming damping is small ) in seconds :

asked Dec 11, 2018 by pady_1

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Statement-1: The number of ways of distributing 10 identical balls in 4 distinct boxes such that no box is empty is $^9C_3$ Statement-2 : The number of ways of choosing any 3 places from 9 different places is $^9C_3$.

asked Dec 11, 2018 by pady_1

0 answers

A ball is made of a material of density $\rho$ where $\rho_{oil} < \rho < \rho_{water}$ with $\rho_{oil}$ and $\rho_{water}$ representing the densities of oil and water, respectively. The oil and water are immiscible. If the above ball is in equilibrium in a mixture of this oil and water, which of the following pictures represents its equilibrium position ?

asked Dec 11, 2018 by pady_1

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In which of the following arrangements, the sequence is not strictly according to the property written against it ?

asked Nov 29, 2018 by pady_1

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The quadratic equations $x^2 – 6x + a = 0$ and $x^2 – cx + 6 = 0$ have one root in common. The other roots of the first and second equations are integers in the ratio 4 : 3. Then the common root is

asked Nov 29, 2018 by pady_1

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Let $f: R\to R$ be a function defined by $f(x) = min \{ x + 1, |x| + 1\}$. Then which of the following is true ?

asked Nov 29, 2018 by pady_1

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The flux linked with a coil at any instant 't' is given by : $\phi = 10t^2 - 50 t + 250$ The induced emf at $t =3s$ is :

asked Nov 13, 2018 by pady_1

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If $x \frac{dy}{dx} = y (\log y - \log x + 1)$, then the solution of the equation is :

asked Nov 5, 2018 by pady_1

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A system goes from A to B via two process I and II as shown in figure. If $\Delta U_1$ and $\Delta U_2$ are the changes in internal energies in the process I and II respectively, then :

asked Nov 5, 2018 by pady_1

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$\begin{align} \displaystyle \lim_{n \to \infty} \displaystyle\sum_{r=1}^{n} \frac{1}{n} e^{^{\frac{r}{n}}} \end{align}$ is

asked Nov 5, 2018 by pady_1

0 answers

Three objects, A : (a solid sphere), B : (a thin circular disk) and C : (a circular ring), each have the same mass M and radius R. They all spin with the same angular speed $\omega$ about their own symmetry axes. The amounts of work (W) required to bring them to rest, would satisfy the relation

asked Aug 21, 2018 by pady_1

1 answer

The correct statement regarding electrophile is :

asked Aug 21, 2018 by pady_1

1 answer

Consider the nitration of benzene using mixed conc. $H_2SO_4$ and $HNO_3$. If a large amount of $KHSO_4$ is added to the mixture, the rate of nitration will be :

asked Aug 21, 2018 by pady_1

1 answer

The rate constant of the reaction $A \to B$ is $0.6 \times 10^{-3} $mole per second. If the concentration of A is 5 M, then cencentration of B after 20 minutes is -

asked Aug 21, 2018 by pady_1

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A beam of light of $\lambda$ = 600 nm from a distant source falls on a single slit 1 mm wide and the resulting diffraction pattern is observed on a screen 2m away. The distance between first dark fringes on either side of the central bright fringe is :

asked Aug 20, 2018 by pady_1

1 answer

The half-life of a radioactive isotope ‘X’ is 20 years. It decays to another element ‘Y’ which is stable. The two elements ‘X’ and ‘Y’ were found to be in the ratio 1 : 7 in a sample of a given rock. The age of the rock is estimated to be -

asked Aug 20, 2018 by pady_1

1 answer

The magnifying power of a teloscope is 9. When it is adjusted for parallel rays the distance between the objective and eyepiece is 20 cm. The focal length of lenses are

asked Aug 20, 2018 by pady_1

1 answer

The decreasing order of wavelength of infrared, microwave, ultraviolet and gamma rays is :

asked Aug 16, 2018 by pady_1

1 answer

A lens having focal length f and aperture of diameter d forms an image of intensity I. Aperture of diameter $\frac{d}{2}$ in central region of lens is covered by a black paper. Focal length of lens and intensity of image now will be respectively –

asked Jul 26, 2018 by pady_1

1 answer

Three concentric spherical shells have radii a, b, and c(a < b < c) and have surface charge densities $\sigma$,$-\sigma$ and $\sigma$ respectively. If $V_A,V_B,V_C$ denote the potentials of the three shells, then, for c = a + b, we have :

asked Jul 26, 2018 by pady_1

1 answer

The ground state energy of hydrogen atom is –13.6 eV. When its electron is in the first excited state, its excitation energy is -

asked Jul 26, 2018 by pady_1

1 answer

The primary and secondary coils of a transformer have 50 and 1500 turns respectively. If the magnetic flux $\phi$ linked with the primary coil is given by $\phi = \phi_0 + 4t$, where $\phi$ is in webers, t is time in seconds and $\phi_0$ is a constant, the output voltage across the secondary coil is :

asked Jul 26, 2018 by pady_1

1 answer

Two sound waves with wavelength 5.0 m and 5.5 m respectively, each propagate in a gas with velocity 330 m/s. We expect the following number of beats per second:-

asked Jul 25, 2018 by pady_1

1 answer

Choose the only false statement from the following-

asked Jul 24, 2018 by pady_1

1 answer

Three particles, each of mass m gram, are situated at the vertices of an equilateral triangle ABC of side l cm. (as shown in the figure). The moment of inertia of the system about a line AX perpendicular to AB and in the plane of ABC, in gram$\; cm ^2$ units will be :-

asked Jul 24, 2018 by pady_1

1 answer

The volume occupied by an atom is greater than the volume of the nucleus by a factor of about

asked Jul 24, 2018 by pady_1

1 answer

The given truth table is for which logic gate : -

asked Jul 23, 2018 by pady_1

1 answer

For a coil having $L=2$ mh, current flow through it is $I = t^2 e^{-t}$ then the time at which emf become zero :-

asked Jul 20, 2018 by pady_1

1 answer

For the adjoining diagram, a triangular lamina is shown the correct relation between $I_1$, $I_2$ & $I_3$ is (I – moment of inertia)

asked Jul 20, 2018 by pady_1

1 answer

A standing wave having 3 nodes and 2 antinodes is formed between 1.21 Å distance then the wavelength is :

asked Jun 15, 2018 by pady_1

1 answer

Find the rule for pattern shown below, 800 850 900 950 1000

asked Dec 31, 2015 by pady_1

1 answer

Which of the following letters does not have any line of symmetry?

asked Dec 31, 2015 by pady_1

1 answer

Divide 63.924 g by 20 g.

asked Dec 31, 2015 by pady_1

1 answer

Write the fraction $\large\frac{9}{36}$ in simplest/lowest form.

asked Dec 31, 2015 by pady_1

0 answers

What % is 30 of 150?

asked Dec 31, 2015 by pady_1

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