Recent questions in Archives

Dissolving 120 g of a compound of (mol .wt .60) in 1000 g of water gave a solution of density 1.12 g/mL . The molarity of the solution is :

asked May 6, 2014 by yamini.v

0 answers

At a certain temperature only $\;50 \%\;$ HI is disassociated into $\;H_{2}\;$ and $\;I_{2}\;$ at equilibrium . The equilibrium constant is :

asked May 6, 2014 by yamini.v

0 answers

The standard electrode potentials $\;(E^{0}_{\large\frac{M}{M}}+)\;$ of four metals A,B,C and D are -1.2 V ,0.6 V ,0.85 V and -0.76 V , respectively .The sequence of deposition of metals on applying potential is :

asked May 6, 2014 by yamini.v

0 answers

Van der waal's equation for a gas is stated as , $\;p=\large\frac{nRT}{V-nb}- a(\large\frac{n}{v})^{2}\;$ .This equation reduces to the perfect gas equation $\;p=\large\frac{nRT}{V}\;$ when ,

asked May 5, 2014 by yamini.v

1 answer

In a face centered cubic lattice atoms A are at the corner points and atoms B at the face centered points .If atom is missing from one of the face centered points, the formula of the ionic compound is :

asked May 5, 2014 by yamini.v

0 answers

An n-p-n transistor has three leads A,B and C . Connecting B and C by moist fingers A, to the positive lead of an ammeter , and C to the negative lead of the ammeter , one finds large deflection . Then A,B and C refer respectively to :

asked May 5, 2014 by yamini.v

0 answers

A transmitting antenna at the top of a tower has a height 32 m and the height of the receiving antenna is 50 m .What is the maximum distance between them for satisfactory communication in line of sight (LOS) mode ?

asked May 5, 2014 by yamini.v

2 answers

If the binding energy of the electron in a hydrogen atom is 13.6 eV , the energy required to remove the electron from the first exited state of $\;Li^{++}\;$ is :

asked May 5, 2014 by yamini.v

1 answer

For which of the following particles will it be most difficult to experimentally verify the de-Broglie relationship ?

asked May 3, 2014 by yamini.v

1 answer

The focal lengths of objective lens and eye lens of a Gallelian Telescope are respectively 30 cm and 3.0 cm . Telescope produces virtual , erect image of an object situated far away from it at least distance of distinct vision from the eye lens . In this condition , the magnifying power of the Gallelian Telescope should be :

asked May 3, 2014 by yamini.v

0 answers

A driver looking up through the water sees the outside world contained in a circular horizon .The refractive index of water is $\;\large\frac{4}{3}\;$ , and the diver's eyes are 15 cm below the surface water . Then the radius of the circle is :

asked May 3, 2014 by yamini.v

0 answers

When the rms voltages $\;V_{L}\;,V_{C}\;$ and $\;V_{R}\;$ are measured respectively across the inductor L , the capacitor C and the resistor R in a series LCR circuit connected to an AC source ,it is found that the ratio $\;V_{L} : V_{C} : V_{R} = 1 : 2: 3\;$ . If the rms voltage of the AC source is 100 V , then $\;V_{R}\;$ is close to :

asked May 3, 2014 by yamini.v

0 answers

The magnetic field of earth at the equator is approximately $\; 4 \times 10^{-5} \;T\;$ The radius of earth is $\;6.4 \times 10^{6}\;m\;$ .Then the dipole moment of the earth will be nearly of the order of :

asked May 3, 2014 by yamini.v

1 answer

The mid - points of two small magnetic dipoles of length d in end - on positions , are separated by a distance x, (x >> d) . The force between them is proportional to $\;x^{-n}\;$ where n is :

asked May 3, 2014 by yamini.v

0 answers

A d.c. main supply of e.m.f. 220 V is connected across a storage battery of e.m.f. 200 V through a resistance of $\;\Omega\;$ . The battery terminals are connected to an external resistance ' R ' . The minimum value of ' R ' , so that a current passes through the battery to charge it is :

asked May 3, 2014 by yamini.v

0 answers

Three capacitance ,each of $\;3 \;mu F\;$ , are provided . These can not be combined to provide the resultant capacitance of :

asked May 3, 2014 by yamini.v

0 answers

The magnitude of the average electric field normally present in the atmosphere just above the surface of the Earth is about 150 N/C , directed inward towards the centre of the earth .This gives the total net surface charge carried by the Earth to be : $\;[Given \;\in_{0} =8.85 \times 10^{-12} \;C^{2}/N-m^{2} , R_{E} = 6.37 \times 10^{6}\;m\;]$

asked May 3, 2014 by yamini.v

0 answers

A transverse wave is represented by : $\;y=\large\frac{10}{\pi} sin (\large\frac{2 \pi}{T} t - \large\frac{2 \pi}{\lambda} x)\;$ . For what value of the wavelength the wave velocity is twice the maximum particle velocity ?

asked May 3, 2014 by yamini.v

1 answer

Modern vacuum pumps can evacuate a vessel down to pressure of $\;4.0 \times 10^{-15}\;atm\;$ .at room temperature (300 K). Taking $\;R=8.3 JK^{-1}mole^{-1},1\;atm=10^{5}\;Pa\;$ and $\;N_{Avogadro}=6 \times 10^{23}\;mole^{-1}\;$ the mean distance between molecules of gas in an evacuated vessel will be the order of :

asked May 3, 2014 by yamini.v

0 answers

The equation of state for a gas is given by $\;PV=nRT+ \alpha V\;$ ,where n is the number of moles and $\;\alpha\;$ is a positive constant . The initial temperature and pressure of one mole of the gas contained in a cylinder are $\;T_{0}\;$ and $\;P_{0}\;$ respectively . The work done by the gas when its temperature doubles isobarically will be :

asked May 3, 2014 by yamini.v

0 answers

Water of volume 2 L in a closed container is heated with a coil of 1kW .While water is heated , the container loses energy at a rate of 160 J/s . In how much time will the temperature of water rise from $\;27^{0}C\;$ to $\;77^{0}C\;$ ? (Specific heat of water is 4.2 kJ/kg and that of the container is negligible) .

asked May 3, 2014 by yamini.v

0 answers

A capillary tube is immersed vertically in water and the height of the water column is x .When this arrangement is taken into a mine of depth d , the height of the water column is y .If R is the radius of the earth , the ratio $\;\large\frac{x}{y}\;$ is :

asked May 3, 2014 by yamini.v

0 answers

The amplitude of a simple pendulum , oscillating in air with a small spherical bob, decreases from 10 cm to 8 cm in 40 seconds .Assuming that Stokes law is valid , and ratio of the coefficient of viscosity of air to that of carbon dioxide is 1.3 , the time in which amplitude of this pendulum will reduce from 10 cm to 5 cm in carbondioxide will close to (ln 5=1.601, ln 2=0.693)

asked May 3, 2014 by yamini.v

0 answers

In materials like aluminium and copper , the correct order of magnitude of various elastic modulii is :

asked May 3, 2014 by yamini.v

0 answers

India's mangalyan was sent to the mars by launching it into a transfer orbit EOM around the sun .It leaves the earth at E and meets mars at M.If the semi - major axis of earth's orbit is $\;a_{e}=1.5 \times 10^{11} m\;$ , that of Mar's orbit $\;a_{m}=2.28 \times 10^{11} m\;$ , taken Kepler's law give the estimate of time for mangalyan to reach Mars from Earth to be close to :

asked May 3, 2014 by yamini.v

1 answer

A cylinder of mass $\;M_{c}\;$ and sphere of mass $\;M_{s}\;$ are placed at points A and B of two inclines, respectively .(see figure) . If they role on the incline without slipping such that their accelerations are the same , then the ratio $\; \large\frac{sin \theta_{c}}{sin\theta_{s}}\;$ is :

asked May 3, 2014 by yamini.v

0 answers

Two bodies of masses 1 kg and 4 kg are connected to a vertical spring , as shown in the figure . The smaller mass executes simple harmonic motion of angular frequency 25 rad/s , and amplitude 1.6 cm while the bigger mass remains stationary on the ground . The maximum force exerted by the system on the floor is (take g= $\;10 ms^{-2}$ ) .

asked May 3, 2014 by yamini.v

1 answer

A block A of mass 4 kg is placed on another block B of mass 5 kg , and the block B rests on a smooth horizontal table . If the minimum force that can be applied on A so that both the blocks move together is 12 N , the maximum force that can be applied on B for the blocks to move together will be :

asked May 3, 2014 by yamini.v

1 answer

Water is flowing a speed of $\;1.5 ms^{-1} \;$ through a horizontal tube cross - sectional area $\;10^{-2}m^{2}\;$ and you are trying to stop the flow by your palm . Assuming that the water stops immediately after hitting the palm , the minimum force that you must exert should be (density of water = $\; 10^{3}\;kgm^{-3}\;$ ).

asked May 3, 2014 by yamini.v

1 answer

The position of a projectile launched from the origin at t=0 is given by $\;\overrightarrow{r}=(40 \hat{i} + 50 \hat{j}) \;m\;$ at $\;t=2s\;$ . If the projectile was launched at an angle $\;\theta\;$ from the horizontal , then $\;\theta\;$ is (take $\;g=10\;ms^{-2}$ ).

asked May 2, 2014 by yamini.v

0 answers

An experiment is performed to obtain the value of acceleration due to gravity g by using a simple pendulum of length L .In this experiment time for 100 oscillations is measured by using a watch of 1 second least count and the value is 90.0 seconds .The length L is measured by using a meter scale of least count 1 mm and the value is 20.0 cm.The error in the determination of g would be :

asked May 2, 2014 by yamini.v

1 answer

If $\;\alpha ,\beta \neq o\;$ , and $\;f(n)=\alpha^{n} + \beta^{n}\;$ and $\;\begin{vmatrix} 3 & 1+f(1) & 1+f(2) \\ 1+f(1) & 1+f(2) & 1+f(3) \\ 1+f(2) & 1+f(3) & 1+f(4)\end{vmatrix} = K (1-\alpha)^{2}(1-\beta)^{2}(\alpha-\beta)^{2}\;$ , then $\;K\;$ is equal to :

asked May 2, 2014 by yamini.v

0 answers

The statement $\;\sim(p \leftrightarrow \sim q)\;$ is :

asked May 2, 2014 by yamini.v

0 answers

A bird is sitting on the top of a vertical pole 20 m high and its elevation from a point O on the ground is $\;45^{0}\;$ . It flies off horizontally straight way from the point O . After one second ,the elevation of the bird from O is reduced to $\;30^{0}\;$ . Then the speed in $(m/s)\;$ of the bird is :

asked May 2, 2014 by yamini.v

0 answers

Let $\;f_{k}(x)= \large\frac{1}{k}(sin^{k}x+cos^{k}x)\;$ where $\;x \in R\;$ and $\;k \geq 1\;$ . Then $\;f_{4}(x) - f_{6}(x)$ equals :

asked May 2, 2014 by yamini.v

0 answers

The variance of first 50 even natural numbers is :

asked May 2, 2014 by yamini.v

1 answer

Let A and B be two events such that $\;P (\overline{A \cup B}) = \large\frac{1}{6}\;,P (\overline{A \cap B}) = \large\frac{1}{4} \;$ where $\;\overline{A}\;$ stands for the compliment of the event A .Then the events A and B are :

asked May 2, 2014 by yamini.v

0 answers

If $\;[\overrightarrow{a} \times \overrightarrow{b} \;\;\overrightarrow{b}\times \overrightarrow{c} \;\;\overrightarrow{c} \times \overrightarrow{a} ]= \lambda [\overrightarrow{a}\;\overrightarrow{b}\;\overrightarrow{c}]^{2}\;$ then $\;\lambda\;$ is equal to :

asked May 2, 2014 by yamini.v

0 answers

The angle between the lines whose direction cosines satisfy the equations $\;l+m+n=0\;$ and $\;l^{2}=m^{2}+n^{2}\;$ is :

asked May 2, 2014 by yamini.v

0 answers

The image of the line $\;\large\frac{x-1}{3} =\large\frac{y-3}{1} =\large\frac{z-4}{-5}\;$ in the plane $\;2x-y+z+3=0\;$ is the plane :

asked May 2, 2014 by yamini.v

0 answers

The slope of the line touching both the parabolas $\;y^{2}=4x\;$ and $\;x^{2}=-32y\;$ is :

asked May 2, 2014 by yamini.v

0 answers

Let C be the circle with centre at (1,1) and radius=1 . If T is the circle centred at (0,y) ,passing through origin and touching the circle C externally ,then the radius of T is equal to :

asked May 2, 2014 by yamini.v

0 answers

The locus of the foot of perpendicular drawn from the centre of the ellipse $\;x^{2}+3y^{2}=6\;$ on any tangent to it is :

asked May 2, 2014 by yamini.v

1 answer

Let a,b,c and d be non-zero numbers .If the point of intersection of the lines $\;4ax+2ay+c=0\;$ and $\;5bx+2by+d=0\;$ lies in the fourth quadrant and is equidistant from the two axis then :

asked May 2, 2014 by yamini.v

0 answers

Let PS be the median of the triangle with vertices P(2,2) , Q(6,-1) and R(7,3) . The equation of the line passing through (1,-1) and parallel to PS is :

asked May 2, 2014 by yamini.v

0 answers

Let the population of rabbits surviving at a time t be governed by the differential equation $\; \large\frac{d p(t)}{dt} = \large\frac{1}{2} p(t) -200 \;$ . If $\;p(0) = 100\;$ , then $\;p(t)\;$ equals :

asked May 2, 2014 by yamini.v

1 answer

The area of the region described by $\;A=\{(x,y) : x^{2}+y^{2} \leq 1 \;and\; y^{2} \leq 1-x\}\;$ is :

asked May 2, 2014 by yamini.v

0 answers

The integral $\; \int_{0}^{\pi} \sqrt{1+4sin^{2} \large\frac{x}{2}-4 sin \large\frac{x}{2}} dx\;$ equals :

asked May 2, 2014 by yamini.v

0 answers

The integral $\;\int (1+x-\large\frac{1}{x})\;e^{x+\large\frac{1}{x}} dx\;$ is equal to :

asked May 2, 2014 by yamini.v

0 answers

If x=-1 and x=2 are extreme points of $\;f(x) =\alpha log|x|+ \beta x^{2}+x\;$ then :

asked May 2, 2014 by yamini.v

0 answers

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