Recent questions tagged 2017

Which of the following statements are correct ?

asked Oct 26, 2017 by meena.p

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The acceleration due to gravity at a height I km above the earth is the same as at a depth d below the , surface of earth. Then :

asked Oct 26, 2017 by meena.p

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The given electricaI network is equivalent to

asked Oct 25, 2017 by meena.p

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A spring of force constant k is cut into lengths of ratio $I : 2 :3$ . They are connected in series and the, new force constant is 'K'.- Then they are connected is parallel and force constant is k". Then k, : k, is

asked Oct 25, 2017 by meena.p

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Which one of the following represents; forward bias diode?

asked Oct 11, 2017 by meena.p

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In a common emitter transistor amplifier the audio signal voltage across the collector is $3 \Omega$. If current gain is 100 and the base resistance is $2 k \Omega$ , the voltage and power gain of the amplifier is :

asked Oct 11, 2017 by meena.p

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Two cars moving in opposite directions approach each other with speed of 22 m/ s and 16.5 m/s respectively. The driver of the first car blows a horn having a frequency 400 Hz . The frequency heard by the driver of the second car is [velocity of sound 340 m/s]

asked Oct 10, 2017 by meena.p

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A physical quantity of the dimensions of length that can be formed out of c, G and $\large\frac{e^2}{4 \pi \in_0}$ is [c is velocity of light, G is universal constant of gravitation and e is charge ] :

asked Oct 10, 2017 by meena.p

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The photo electric threshold wave length of silver is $3250 \times 10^{-10}\;m$ . The velocity of the electrons ejected from a silver surface by ultraviolet light of wavelength $2536 \times 10^{-10}\;m$ is : (Given $h=4.14 \times 10^{-10} \;eVs$ and $c= 3 \times 10^{8} \;ms^{-1})$

asked Oct 10, 2017 by meena.p

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A capacitor is charged by a battery. The battery is removed and another identical uncharged capacitor is connected in parallel. The total electrostatic energy of resulting system :

asked Oct 10, 2017 by meena.p

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Thermodynamic processes are indicated in the following diagram.

asked Oct 10, 2017 by meena.p

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A particle executes linear simple harmonic motion with an amplitude of 3 cm. When the particle is at 2 cm from the mean position, the magnitude of its velocity is equal to that of its acceleration.- Then its time period in seconds is

asked Oct 10, 2017 by meena.p

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Young's double slit experiment is first performed in air and then in a medium other than air. It is found that 8th bright fringe in the medium lies where 5th dark fringe lies in air. The refractive index of the medium is nearly

asked Oct 10, 2017 by meena.p

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The ratio of wavelengths of the last line of Balmer series and the last line of Lyman series is

asked Oct 10, 2017 by meena.p

1 answer

The diagrams below, shown, regions of equipotentials : A positive charge is moved from A to B in each diagram.

asked Oct 10, 2017 by meena.p

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Two rods A and B of different materials are welded together as shown in figure. Their thermal conductivities are $K_1$ and $K_2$. The thermal conductivity of the composite rod will be

asked Oct 10, 2017 by meena.p

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Suppose the charge of a proton and an eleckon differ slightly. One of them is - e, the other is $(e + \Delta e)$. If the net of electrostatic force and gravitational force between two hydrogen atoms placed at a distance d much greater than atomic size. apart is zero, then $\Delta_e$ is of the order of [Given mass of hydrogen $m_h= 1.67 \times 10^{27}\;kg]$

asked Oct 7, 2017 by meena.p

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The x and y coordinates of the particle at any time are $x= 5t - 2t^2$ and $y = 10t$ respectivelv, where r and y are in meters and t in seconds. The acceleration of the particle at $t = 2s$ is

asked Oct 7, 2017 by meena.p

1 answer

Figure shows a circuit that contains three identical resistors with resistance R=9.0 O each, two identical inductors with inductance L=2.0 mH each, and an ideal battery with emf e: 18 V. The current 'i' through the battery just after the switch closed is,.....

asked Oct 7, 2017 by meena.p

1 answer

One end of string of length I is connected to a particle of mass 'nf and the other end is connected to a small peg on a smooth horizontal table. If the particle moves in circle with speed 'u', the net force on the particle (directed towards center) will be ([ represents the tension in the string)

asked Oct 7, 2017 by meena.p

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The de - Brogile wave length of a neutron in thermal equilibrium with heavy water at a temperature T and mass m , is

asked Oct 7, 2017 by meena.p

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A 250 N turn rectangular coil of length $2.1\;cm$ and width $1.25\;cm$ carries a current of $85 \mu A$ and subjected to magnetic field of strength $0.85\;T$ Work done for rotating the coil by $180^{\circ}$ against the torque is :

asked Oct 7, 2017 by meena.p

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A U tube with both ends open to the atmosphere, is partially filled rvith u,ater. Oil, which is imeriscible with water, is poured into one side until itstands at a distance of 10 mtrr above the water level on the other side. Meanwhile the water rises by $65\; mm$ from its original level (see diagram). The density of the oil is :

asked Oct 7, 2017 by meena.p

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Radioactive material 'A' has decay constant $8 \lambda$ and material 'B' has decay constant $\lambda$. Initially they have same number of nuclei. After what time, the ratio of number of nuclei of material 'B' to that 'A' will be $\large\frac{1}{e} $?

asked Oct 7, 2017 by meena.p

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A gas mixture consists of 2 moles of O, and 4 moles of Ar at temperature T. Neglecting all vibrational modes, the totalintemal energv of l.he system is :

asked Oct 7, 2017 by meena.p

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A potentiometer is an accurate and versatile device to make elechical measurements of E.M.F. because the method involves :

asked Oct 7, 2017 by meena.p

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Let the refractive index of a denser medium with respect to a rarer medium be $n_{12}$ and its critical angle be $\theta C$ . At an angle of incidence A when light is travelling from denser medium to rarer medium, a part of the light is reflected and the rest is refracted and the angle between reflected and refracted rays is 908. Angle A is given by :

asked Aug 9, 2017 by meena.p

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Magnetic field in a plane electromagnetic wave is given by $\overrightarrow{B} =B_0 \sin (kx+ \omega t) \hat j T$ Expression for corresponding electric field will be : Where c is speed of light.

asked Aug 9, 2017 by meena.p

1 answer

The following statement $(p \to q)\to [(\approx p \to q)\to q]$ is :

asked Aug 4, 2017 by meena.p

1 answer

Let a vertical tower AB have its end A on the level ground. Let C be the mid-point of AB and P be a point on the ground such that $AP=2AB$. If $\angle BPC=\beta$, then $\tan \beta$ is equal to :

asked Aug 4, 2017 by meena.p

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If $5(tan^2 x−cos^2 x)=2cos 2x+9$, then the value of $\cos 4x$ is :

asked Aug 4, 2017 by meena.p

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If two different numbers are taken from the set {0, 1, 2, 3, ......, 10}; then the probability that their sum as well as absolute difference are both multiple of 4, is :

asked Aug 4, 2017 by meena.p

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For three events A, B and C, P(Exactly one of A or B occurs) =P(Exactly one of B or C occurs) =P(Exactly one of C or A occurs)= $\large\frac{1}{4}$ and P(All the three events occur simultaneously)=$\large\frac{1}{16}$.Then the probability that at least one of the events occurs, is :

asked Aug 4, 2017 by meena.p

1 answer

A box contains 15 green and 10 yellow balls. If 10 balls are randomly drawn, one-by-one, with replacement, then the variance of the number of green balls drawn is :

asked Aug 4, 2017 by meena.p

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Let $\overrightarrow{a}= 2\hat i +\hat j -2 \hat k$ and $\overrightarrow{b}= \hat i +\hat j $. Let $\overrightarrow{c}$ be a vector such that $\bigg|\overrightarrow{c}-\overrightarrow{a} \bigg|= 3,\bigg|(\overrightarrow{a} \times \overrightarrow{b} ) \times \overrightarrow{c} \bigg|=3$and the angle between $\overrightarrow{c}$ and $\overrightarrow{a} \times \overrightarrow{b}$ be $30^{\circ}$. Then $\overrightarrow{a}.\overrightarrow{c}$ is equal to :

asked Aug 4, 2017 by meena.p

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If the image of the point P(1, −2, 3) in the plane, $2x+3y−4z+22=0$ measured parallel to the line, $\large\frac{x}{1}=\frac{y}{4}=\frac{z}{5}$ is Q, then PQ is equal to :

asked Aug 4, 2017 by meena.p

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The distance of the point (1, 3, −7) from the plane passing through the point $(1, −1, −1),$ having normal perpendicular to both the lines $\large\frac{x-1}{1}=\frac{y+2}{-2}=\frac{z-4}{3}$ and $\large\frac{x-2}{2}=\frac{y-1}{-1}=\frac{z+7}{-1}$, is:

asked Aug 4, 2017 by meena.p

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A hyperbola passes through the point $P( \sqrt {2} , \sqrt{3} )$ and has foci at $(\pm 2, 0)$. Then the tangent to this hyperbola at P also passes through the point :

asked Aug 4, 2017 by meena.p

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The eccentricity of an ellipse whose centre is at the origin is $\large\frac{1}{2}$ . If one of its directrices is $x=−4,$ then the equation of the normal to it at $\bigg(1,\large\frac{3}{2}\bigg)$ is :

asked Aug 4, 2017 by meena.p

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The radius of a circle, having minimum area, which touches the curve $y=4−x^2$ and the lines, $y=|x|$ is :

asked Aug 4, 2017 by meena.p

1 answer

Let k be an integer such that the triangle with vertices (k, −3k), (5, k) and (−k, 2) has area 28 sq. units. Then the orthocentre of this triangle is at the point:

asked Aug 4, 2017 by meena.p

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If $(2+\sin x) \large\frac{dy}{dx}$$+(y+1) \cos x=0$ and $y(0)=1$, then $y \bigg(\large\frac{\pi}{2} \bigg)$ is equal to :

asked Aug 4, 2017 by meena.p

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The area (in sq. units) of the region $\{(x, y) : x/0, x+y≤3, x2≤4y \;and\; y≤1+ x \}$ is :

asked Aug 4, 2017 by meena.p

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The integral $\int \limits_{\pi/4}^{3 \pi/4} \large\frac{dx}{1+\cos x}$ is equal to :

asked Aug 4, 2017 by meena.p

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Let $ I_n= \int \tan^n x dx , (n > 1)$ If $I_4+I_6=a \tan^5 x+bx^5+C$ where C is a constant of integration, then the ordered pair (a, b) is equal to :

asked Aug 3, 2017 by meena.p

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Twenty meters of wire is available for fencing off a flower-bed in the form of a circular sector. Then the maximum area (in sq. m) of the flower-bed, is :

asked Aug 3, 2017 by meena.p

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The normal to the curve $y(x−2)(x−3)=x+6$ at the point where the curve intersects the y-axis passes through the point :

asked Aug 3, 2017 by meena.p

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If for $x \in \bigg( 0, \large\frac{1}{4} \bigg)$ the derivative of $\tan ^{-1} \bigg( \large\frac{6x \sqrt x}{1-9x^3}\bigg)$ is $\sqrt x .g(x) $ then $g(x)$ equals

asked Aug 3, 2017 by meena.p

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$\lim_{x \to \large\frac{\pi}{2}} \Large\frac{\cot x - \cos x}{(\pi -2x)^3}$ equals :

asked Aug 1, 2017 by meena.p

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Let $a, b, c \in R$. If $f(x)=ax^2 +bx+c$ is such that $a+b+c=3$ and $f (x+y)=f(x)+f(y)+xy, ∀ x, y \in R$, then $\sum\limits_{n=1}^{90} f(n) $ is equal to :

asked Aug 1, 2017 by meena.p

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