Recent questions tagged 2011

Two uniform stretched string A and B, made of steel , are vibrating under the same tension. If the first overtone of A is equal to the second overtone of B and if the radius of A is twice that of B, the ratio of the lengths of the strings is :

asked Sep 24, 2013 by meena.p

1 answer

The wavelengths of two sound notes in air are $\large\frac{40}{195}\;$$m$ and $\large\frac{40}{193}\;$$m$. Each note produces 9 beats per second separately with a third note of fixed frequency. The velocity of sound in air in m/s is:

asked Sep 24, 2013 by meena.p

1 answer

Two slabs A and B of different materials but of the same thickness are joined and to end to form a composite slab. The thermal conductivities of A and B are $'k_1'$ and $'k_2$ respectively. A steady temperature distance of $12^{\circ}$ is maintained across the composite slab. If $k_1=\large\frac{k_2}{2}$, the temperature difference across slab A is

asked Sep 24, 2013 by meena.p

1 answer

During an adiabatic process, the pressure of a gas is proportional to the cube of its temperature. The value of $C_p/C_v$ for that gas is :

asked Sep 24, 2013 by meena.p

1 answer

A reversible engine converts one-sixth of the heat supplied into work. When the temperature of the sink is reduced by $62^{\circ}C$, the efficiency of the engine is doubled. The temperatures of the source and skin are:

asked Sep 24, 2013 by meena.p

1 answer

An insulated cylindrical vessel filled with an insulated piston of negligible weight and negligible thickness at the mid point of the vessel. The cylinder contains a gas at $0^{\circ}C$. When the gas is heated to $100^{\circ}$, the piston moves through a length of $5 \;cm$. Length of the cylindrical vessel is cm is :

asked Sep 24, 2013 by meena.p

1 answer

A non-conducting body floats in a liquid at $20^{\circ}C$ with $\large\frac{2}{3}$ of its volume immersed in the liquid. When liquid temperature is increased to $100^{\circ}C,\large\frac{3}{4}$ of body's volume is immersed in the liquid . Then the coefficient of real expansion of the liquid is (neglecting the expansion of the liquid):

asked Sep 24, 2013 by meena.p

1 answer

A large open tank has two holes in the wall. One is a square hole of side $'L'$ at a depth $'y'$ from the top and the other is a circular hole of radius R at a depth $'4y'$ from the top. When the tank is completely filled with water, the quantities of water flowing out per second from the two holes are the same. Then value of R is :

asked Sep 24, 2013 by meena.p

1 answer

If two soap bubbles of different radii are connected by a tube, then :

asked Sep 24, 2013 by meena.p

1 answer

Two blocks of masses $1\;kg$ and $2\;kg$ are connected by are connected by a metal wire going over a smooth pulley. The breaking stress of metal is $\large\frac{40}{3 \pi}$$\times 10^6\;Nm^{-2}$.What should be the minimum radius of wire used if it should not break? $(g=10\;m/s^{-2})$

asked Sep 24, 2013 by meena.p

2 answers

A simple harmonic oscillator consists of a particle of mass $'m'$ and an ideal spring with spring constant $'k'$. The particle oscillates with a time period 'T'. The spring is cut into two equal parts. If one part oscillates with the same particle , the time period will be :

asked Sep 24, 2013 by meena.p

1 answer

$\mathbf{Assertion\; (A)}$: An astronaut inside a massive spaceship orbiting around the earth will experience a finite but small gravitational force.$\mathbf{Reason\;(R):}$ The centripetal force necessary to keep the spaceship in orbit around the earth is provided by the gravitational force between the earth and the spaceship.

asked Sep 24, 2013 by meena.p

1 answer

A thin hollow sphere of mass $'m'$ is completely filled with a liquid of mass $'m'$. When the Sphere rolls with a velocity $'c'$, kinetic energy of the system is (neglect friction):

asked Sep 24, 2013 by meena.p

1 answer

Two uniform circular discs having the same mass and the same thickness but different radii are made from different materials. The disc with the smaller rotational inertia is:

asked Sep 24, 2013 by meena.p

1 answer

A uniform chain of length $L$ is lying on the horizontal table . If the coefficient of friction between the chain and the table top is $\mu'$ , what is the maximum length of the chain that can hang over the edge of the table without disturbing the rest of the chain on the table?

asked Sep 24, 2013 by meena.p

2 answers

A circular disc of radius $'R'$ is removed from a bigger circular disc of radius $'2R'$ such that the circumference of the disc touch. The center of mass of the new disc is at a distance $'\alpha R'$ from the center of the bigger disc. The value of $\alpha'$ is

asked Sep 24, 2013 by meena.p

1 answer

A ball is let fall from a height $h_0$. It makes n collisions with the earth. After $'n'$ collisions it rebounds with a velocity $;v_n'$ and the ball rises to a height $h_n$ then coefficient of restitution, is given by

asked Sep 24, 2013 by meena.p

1 answer

The maximum tension a rope can withstand is $6\;kg$ wt. The ratio of maximum acceleration with two boys of masses $20\; kg$ can climb up rope at the same time is :

asked Sep 24, 2013 by meena.p

1 answer

$A I N$ pendulum bob is held at an angle $\theta$ from the vertical by a $2\;N$ horizontal force $\overrightarrow {F}$ as shown in figure. The tension in the string supporting the pendulum bob (in Newtons) is

asked Sep 24, 2013 by meena.p

1 answer

A police party is moving in a jeep at a constant speed $v$. They saw a theif at a distance x on a motorcycle which is at rest. The moment the police saw the thief, the thief started at constant acceleration $\alpha$. Which of the following relations is true if the police is able to catch the thief?

asked Sep 23, 2013 by meena.p

1 answer

A certain vector in the $xy$ plane has an $x$ component of 4 m and any component of 10 m. It is then rotated in the $xy$ plane so that its $x-$ component is doubled. Then its new y component is (approximately):

asked Sep 23, 2013 by meena.p

1 answer

The dimensional formula of $\large\frac{1}{2}$$\mu_0H^2(\mu_0$- Permeability of free space and H-magnetic field intensity ) is :

asked Sep 23, 2013 by meena.p

0 answers

In a $p-n$ junction diode the thickness of depletion layer is $2 \times 10^{-6}\;m$ and barrier potential is $0.3\;V$. the intensity of the electric field at the junction is :

asked Sep 23, 2013 by meena.p

1 answer

If $200 \;MeV$ of energy is released in the fission of one nucleus of $^{235}_{92} U$, the number of nuclei that must undergo fission to release an energy of $1000\;J$ is :

asked Sep 23, 2013 by meena.p

1 answer

Calculate the wavelength of the $k_{\alpha}$ line for $z=31$ when $a=5 \times 10^{7}\;Hz^{1/2}$ for a characteristic X-ray spectrum.

asked Sep 23, 2013 by meena.p

1 answer

Two photons of energy $2.5 \;eV$ and $3.6\;eV$ fall on a metal surface of work function $1.5\;eV$. The ratio of the maximum velocities of the photo electrons emitted from the metal surface is :

asked Sep 23, 2013 by meena.p

1 answer

The radius of the circle given by $x^2+y^2+z^2+2x-2y-4z-19=0=x+2y+2z+7,$ is

asked Sep 23, 2013 by meena.p

1 answer

A plane passes through $(2,3,1)$ and is perpendicular to the line having direction ratios $3,-4,7$.The perpendicular distance from the origin to this plane is

asked Sep 23, 2013 by meena.p

1 answer

If the angles made by a straight line with the coordinate axes are $\alpha,\large\frac{\pi}{2},$$ -\alpha, \beta$ then $\beta=$

asked Sep 23, 2013 by meena.p

1 answer

The ratio in which the line joining $(2,-4,3)$ and $(-4,5,-6)$ is divided by the plane $3x+2y+z-4$ is

asked Sep 23, 2013 by meena.p

1 answer

The polar equation of the line perpendicular to the line $\sin \theta- \cos \theta=\large\frac{1}{r}$ and passing through the point $\bigg(2, \large\frac{\pi}{6}\bigg)$ is

asked Sep 23, 2013 by meena.p

1 answer

The angle between the asymptotes of the hyperbola $x^2-3y^2=3$ is

asked Sep 23, 2013 by meena.p

1 answer

The eccentricity of the ellipse $x^2+4y^2+2x+16y+13=0$ is

asked Sep 23, 2013 by meena.p

1 answer

If the straight line $y=mx+c$ is parallel to the axis of the parabola $y^2=lx$ and intersects the parabola at $\bigg ( \large\frac{c^2}{8}$$,c\bigg)$ then the length of the latus rectum is

asked Sep 23, 2013 by meena.p

1 answer

If a chord of the parabola $y^2=4x$ passes through its focus and makes an angle $\theta$ with the $X-axis,$ then its length is

asked Sep 23, 2013 by meena.p

1 answer

The point of contact the circles $x^2+y^2+2x+2y+1=0$ and $x^2+y^2-2x+2y+1=0$ is

asked Sep 23, 2013 by meena.p

1 answer

If the circle $x^2+y^2+8x-4y+c=0$ touches the circle $x^2 +y^2+2x+4y-11=0$ externally and cuts the circle $x^2+y^2-6x+8y+k=0$ orthogonally then $k=$

asked Sep 23, 2013 by meena.p

1 answer

If the lines $3x+4y-14=0$ and $6x+8y+7=0$ are both tangents to a circle, then its radius is

asked Sep 23, 2013 by meena.p

1 answer

Aline segment $AM=a$ moves in the $XOY$ plane such that $AM$ is parallel to the $x-axis$. If A moves along the circle $x^2+y^2=a^2$, then the locus of M is

asked Sep 23, 2013 by meena.p

1 answer

If the line $y=2x+c,$ is a tangent to the circle $x^2+y^2=5,$ then a value of c is

asked Sep 23, 2013 by meena.p

1 answer

If $s$ and $p$ are respectively the sum and the product of the slope of the lines $3x^2-2xy-15y^2=0,$ then $s:p=$

asked Sep 23, 2013 by meena.p

1 answer

If $ax^2+2hxy+by^2+2gx+2fy+c=0$ represents a pair of parallel lines then $\sqrt {\large\frac{g^2-ac}{f^2-bc}}=$

asked Sep 23, 2013 by meena.p

1 answer

If one of the lines in the pair of straight lines given by $4x^2+6xy+ky^2=0$ bisects the angle between the coordinate axes, then $k \in$

asked Sep 23, 2013 by meena.p

1 answer

The line joining the points $A(2,0)$ and $B(3,1)$ is rotated through an angle of $45^{\circ}$, about A in the anticlockwise direction. The coordinates of B in the new position

asked Sep 23, 2013 by meena.p

1 answer

The image of the point $(3,8)$ in the line $x+3y=7$ is

asked Sep 23, 2013 by meena.p

1 answer

The number of points $P(x,y)$ with natural numbers as coordinates that the inside the quadrilateral formed by the lines $2x+y=2,y=0$ and $x+y=5 $ is

asked Sep 23, 2013 by meena.p

1 answer

If the vectors $\bar {AB}=-3 \bar {i}+ 4 \bar {k}$ and $\bar {AC}=5 \bar {i}-2 \bar j+4 \bar {k} $ are the sides of a triangle ABC, then the length of the medium through A is

asked Sep 23, 2013 by meena.p

1 answer

The locus of a point such that the sum of its distance from the points $(0,2)$ and $(0,-2)$ is $6,$ is

asked Sep 23, 2013 by meena.p

1 answer

The probability that an individual suffers a bad reaction from an injection is 0.001. The probability that out of 2000 individuals exactly three will suffer bad reaction is

asked Sep 23, 2013 by meena.p

1 answer

The probability distribution of a random variable $X$ is given below :X=x 0 1 2 3 P(X=x) $\frac{1}{10}$ $\frac{2}{10}$ $\frac{3}{10}$ $\frac{4}{10}$ Then the variance of $X$ is

asked Sep 23, 2013 by meena.p

1 answer

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