Recent questions tagged 2011

Let $\alpha, \beta$ be real and $z$ be a complex number. If $z^2 + \alpha z + \beta = 0$ has two distinct roots on the line $Rez=1$, then it is necessary that

asked Dec 11, 2018 by pady_1

0 answers

The value of $\begin{align} \int_0^1 \frac{8 \log (1+x)}{1+x^2} dx \end{align} $ is

asked Dec 11, 2018 by pady_1

0 answers

Let R be the set of real numbers Statement-1 : $A = \{ (x,y) \in R \times R : y - x$ is an integer $\}$ is an equivalence relation on R. Statement-2 : B = $\{ (x,y) \in R \times R : x = \alpha y$ for some rational number $\alpha \}$ is an equivalence relation on R.

asked Dec 11, 2018 by pady_1

0 answers

If $\frac{dy}{dx} = y + 3 > 0$ and $y(0) = 2$, then $y(In2)$ is equal to

asked Dec 11, 2018 by pady_1

0 answers

$\frac{d^2x}{dy^2}$ equals

asked Dec 11, 2018 by pady_1

0 answers

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

$ \displaystyle{\lim_{x \to 2} ( \frac{\sqrt{1-\cos \{ 2 (x-2) \} }}{x-2} } )$

asked Dec 11, 2018 by pady_1

0 answers

The coefficient of $x^7$ in the expansion of $(1 - x - x^2 + x^3)^6$ is

asked Dec 11, 2018 by pady_1

0 answers

If $A = \sin^2 x + \cos^2 x $, then for all real $x$

asked Dec 11, 2018 by pady_1

0 answers

The lines $L_1 : y - x = 0$ an $L_2 : 2x + y =0$ intersect the line $L_3 : y + 2 = 0$ at P and Q respectively. The bisector of the acute angle between $L_1$ and $L_2$ intersect $L_3$ at R. Statement-1 : The ratio PR : RQ equals $2\sqrt{2}:\sqrt{5}$. Statement -2 : In any triangle, bisector of an angle divides the triangle into two similar triangles.

asked Dec 11, 2018 by pady_1

0 answers

This question has Statement-1 and Statement-2. Of the four choices given after the statements, choose the one that best describes the two statements. Statement-1 : A metallic surface is irradiated by a monochromatic light of frequency $v > v_0$ (the threshold frequency). The maximum kinetic energy and the stopping potential are $K_{max}$ and $V_0$ respectively. If the frequency incident on the surface doubled, both the $K_{max}$ and $V_0$ are also doubled. Statement-2 : The maximum kinetic energy and the stopping potential of photoelectrons emitted from a surface are linearly dependent on the frequency of incident light.

asked Dec 11, 2018 by pady_1

0 answers

The half life of a radioactive substance is 20 minutes. The aproximate time interval $(t_2 - t_1)$ between the time $t_2$ when $\frac{2}{3}$ of it has decayed and time $t_1$ and $\frac{1}{3}$ of it had decayed is :

asked Dec 11, 2018 by pady_1

0 answers

100 g of water is heated from $30^{\circ}C$ to $50^{\circ}C$. Ignoring the slight expansion of the water, the change in its internal energy is (specific heat of water is 4148 J/Kg/K) :

asked Dec 11, 2018 by pady_1

0 answers

A water fountain on the ground sprinkles water all around it. If the speed of water coming out of the fountain is $v$, the total area around the fountain that gets wet is :

asked Dec 11, 2018 by pady_1

0 answers

The electrostatic potential inside a charged spherical ball is given by $\phi = \alpha \rho^2 + b$ where r is the distance from the centre, a, b are constants. Then the charge density inside ball is

asked Dec 11, 2018 by pady_1

0 answers

Energy required for the electron excitation in $Li^{++}$ from the first to the third Bohr orbit is :

asked Dec 11, 2018 by pady_1

0 answers

A car is fitted with a convex side-view mirror of focal length 20 cm. A second car 2.8 m behind the first car is overtaking the first car at relative speed of 15 m/s. The speed of the image of the second car as seen in the mirror of the first one is :

asked Dec 11, 2018 by pady_1

0 answers

Direction : The question has a paragraph followed by two statements, Statement-1 and Statement-2. Of the given four alternatives after the statements, choose the one that describes the statements. A thin air film is formed by putting the convex surface of a plane - convex lens over a plane glass plate. With monochromatic light, this film gives an interference pattern due to light reflected from the top (convex) surface and the bottom (glass plate) surface of the film. Statement-1: When light reflects from the air-glass plate interface, the reflected wave suffers a phase change of $\pi$. Statement-2:The centre of the interference pattern is dark.

asked Dec 11, 2018 by pady_1

0 answers

If a wire is stretched to make it 0.1% longer, its resistance will :

asked Dec 11, 2018 by pady_1

0 answers

A Carnot engine operating between temperatures $T_1$ and $T_2$ has efficiency $\frac{1}{6}$. When $T_2$ is lowered by 62 $K$, its efficiency increases to $\frac{1}{3}$. Then $T_1$ and $T_2$ are, respectively :

asked Dec 11, 2018 by pady_1

0 answers

A resistor 'R' and $2 \mu F$ capacitor in series is connected through a switch to 200 V direct supply. Across the capacitor is a neon bulb that lights up at 120 V. Calculate the value of R to make the bulb light up 5 s after the switch has been closed. ($\log_{10} 2.5 = 0.4$)

asked Dec 11, 2018 by pady_1

0 answers

A pulley of radius 2 m is rotated about its axis by a force $F=(20t-5t^2)$ Newton (where t is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation made by the pulley before its direction of motion if reversed, is :

asked Dec 11, 2018 by pady_1

0 answers

Three perfect gases at absolute temperature $T_1, T_2, T_3$ are mixed. The masses of molecules are $m_1, m_2$ and $m_3$ and the number of molecules are $n_1, n_2$ and $n_3$ respectively. Assuming no loss of energy, the final temperature of the mixture is :

asked Dec 11, 2018 by pady_1

0 answers

This question has Statement-1 and Statement-2. Of the four choices given after the statements, choose the one that best describes the two statements. Statement-1 : Sky wave signals are used for long distance radio communication. These signals are in general, less stable than ground wave signals. Statement-2: The state of ionosphere varies from hour to hour, day to day and season to season

asked Dec 11, 2018 by pady_1

0 answers

Water is flowing continuously from a tap having an internal diameter $8 \times 10^{-3}$m. The water velocity as it leaves the tap is $0.4\; ms^{-1}$. The diameter of the water stream at a distance $2 \times 10^{-1}$ m below the lap is close to :

asked Dec 11, 2018 by pady_1

0 answers

A mass M, attached to a horizontal spring, executes S.H.M. with amplitude $A_1$. When the mass M passes through its mean position then a smaller mass m is placed over it and both of them move together with amplitude $A_2$. The ratio of $(\frac{A_1}{A_2})$ is :

asked Dec 11, 2018 by pady_1

0 answers

A thermally insulated vessel contains an ideal gas of molecular mass M and ratio of specific heats $\gamma$. It is moving with speed $v$ and is suddenly brought to rest. Assuming no heat is lost to the surroundings, its temperature increases by :

asked Dec 11, 2018 by pady_1

0 answers

A current I flows in an infinitely long wire with cross section in the form of a semicircular ring of radius R. The magnitude of the magnetic induction along its axis is

asked Dec 11, 2018 by pady_1

0 answers

Let the $x-z$ plane be the boundary between two transparent media. Medium 1 in $z \geq 0$ has a refractive index of $\sqrt{2}$ and medium 2 with $z < 0$ has a refractive index of $\sqrt{3}$. A ray of light in medium 1 given by the vector $\overrightarrow{A} = 6\sqrt{3} \hat{i} + 8 \sqrt{3} \hat{j} - 10 \hat{k}$ is incident on the plane of separation. The angle of refraction in medium 2 is

asked Dec 11, 2018 by pady_1

0 answers

A fully charged capacitor C with initial charge $q_0$ is connected to a coil of self inductance $L$ at $t=0$. The time at which the energy is stored equally between the electric and the magnetic field is :

asked Dec 11, 2018 by pady_1

0 answers

An object moving with a speed of 6.25 m/s, is decelerated at a rate given by : $\frac{dv}{dt} = -2.5 \sqrt{v}$ where $v$ is the instantaneous speed. The time taken by the object, to come to rest, would be :

asked Dec 11, 2018 by pady_1

0 answers

A boat is moving due east in a region where the earth's magnetic field is $5.0 \times 10^{-5} NA^{-1}m^{-1}$ due north and horiontal. The boat carries a vertical aerial 2m long. If the speed of the boat is $1.50 \;ms^{-1}$, the magnitude of the induced emf in the wire of aerial is :

asked Dec 11, 2018 by pady_1

0 answers

Two identical charged spheres suspended from a common point by two massless strings of length $l$ are initially a distance $d(d <<1)$ apart because of their mutual repulsion. The charge begins to leak from both the spheres at a constant rate. As a result the charge approach each other with a velocity v. Then as a function of distance x between them,

asked Dec 11, 2018 by pady_1

0 answers

Two bodies of masses m and 4m are placed at a distance r. The gravitational potential at a point on the line joining them where the gravitational field is zero is :

asked Dec 11, 2018 by pady_1

0 answers

Two particles are executing simple harmonic motion of the same amplitude A and frequency $\omega$ along the $x-axis$. Their mean position is separated by distance $X_0(X_0 > A)$. If the maximum separation between them is $(X_0+ A)$, the phase difference between their motion is :

asked Dec 11, 2018 by pady_1

0 answers

A thin horizontal circular disc is rotating about a vertical axis passing through its centre. An insect is at rest at a point near the rim of the disc. The insect now moves along a diameter of the disc to reach its other end. During the journey of the insect, the angular speed of the disc.

asked Dec 11, 2018 by pady_1

0 answers

Work done in increasing the size of a soap bubble from a radius of 3 cm to 5 cm is nearly (Surface tension of soap solution = $ 0.03 Nm^{-1}$) :

asked Dec 11, 2018 by pady_1

0 answers

A mass m hangs with the help of a string wrapped around a pulley on a frictionless bearing. The pulley has mass m and radius R. Assuming pulley to be a perfect uniform circular disc, the acceleration of the mass m, if the string does not slip on the pulley, is

asked Dec 11, 2018 by pady_1

0 answers

A screw gauge gives the following reading when used to measure the diameter of a wire. Main scale reading : 0 mm Circular scale reading : 52 divisions Given that 1 mm on main scale corresponds to 100 divisions of the circular scale. The diameter of wire from the above date is :

asked Dec 11, 2018 by pady_1

0 answers

The transverse displacement $y(x,t)$ of a wave on a string is given by $y (x,t) = e^{-(ax^2 + bx^2 + 2 \sqrt{ab}\; xt)}$. This represents a

asked Dec 11, 2018 by pady_1

0 answers

There is a restriction endonuclease called EcoRl. What does "co" part in it stand for ?

asked Aug 16, 2018 by pady_1

1 answer

An organism used as a Biofertilizer for raising soyabean crop is :

asked Aug 16, 2018 by pady_1

1 answer

The most common substrate used in distilleries for the production of ethanol is :

asked Aug 16, 2018 by pady_1

1 answer

Given below is a sample of a portion of DNA strand giving the base sequence on the opposite strands. What is so special shown in it ? 5' .............. GAATTC ................ 3' 3' .............. CTTAAG ................. 5'

asked Aug 16, 2018 by pady_1

1 answer

At which stage of HIV infection does one usually shown symptoms of AIDS ?

asked Aug 16, 2018 by pady_1

1 answer

A certain patient is suspected to be suffering from Acquired Immuno Deficiency Syndrome. Which diagnostic technique will you recommend for its detection ?

asked Aug 16, 2018 by pady_1

1 answer

When two unrelated individuals or lines are crossed, the per romance of F1 hybrid is often superior to both parents. This phenomenon is called :

asked Aug 16, 2018 by pady_1

1 answer

Where will you look for the sporozoites of the malarial parasite ?

asked Aug 16, 2018 by pady_1

1 answer

Which one of the following pairs of gases are the major cause of "Green house effect"?

asked Aug 16, 2018 by pady_1

1 answer

Consider the following four conditions (a – d) and select the correct pair of them as adaptation to environment in desert lizards. The conditions : (a) burrowing in soil to escape high temperature (b) losing heat rapidly from the body during high temperature (c) bask in sun when temperature is low (d) insulating body due to thick fatty dermis

asked Aug 16, 2018 by pady_1

1 answer

Ask Questions, Get Answers