Recent questions tagged modelpaper

Define $\alpha$ and $\beta$ of a transistor. How are they related?

asked Jan 29, 2015 by meena.p

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A)Name any two modes of modulation used for pulsed waves. B) What is the order of energy gap in an insulator?

asked Jan 29, 2015 by meena.p

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The sequence of the stepwise decay of radio active nucleus is If the nucleon number and atomic number for $D_2$ are respectively 176 and 71, what are the corresponding values for D and $D_4$ nuclei? Justify your answer.

asked Jan 29, 2015 by meena.p

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Name two factors on which the resisitivity of a given material depends. A carbon resistor has a value of 62 KΩ with a tolerance of 5%. Give the color code of this resistor.

asked Jan 29, 2015 by meena.p

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A straight wire of length of $1.5\;m$ and mass $200\;g$ carries a current of $2A$. It is suspended in mid-air by a uniform horizontal magnetic field B. What is the magnitude of the magnetic field?

asked Jan 29, 2015 by meena.p

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State Lenz’s law. On which law of conservation is it based?

asked Jan 29, 2015 by meena.p

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What is the de-Broglie wavelength of an electron accelerated from rest through a potential difference of V volts?

asked Jan 29, 2015 by meena.p

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How does the electric field of an electric dipole vary with distance?

asked Jan 29, 2015 by meena.p

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What is the ratio of infra red rays to ultra violet rays in vaccum?

asked Jan 29, 2015 by meena.p

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Why are microwaves used in Radar?

asked Jan 29, 2015 by meena.p

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Why does the acceleration of a magnet falling through a long solenoid decrease?

asked Jan 29, 2015 by meena.p

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Draw a circuit diagram and explain the operations of a transistor as a switch .

asked Jan 28, 2015 by meena.p

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(a)Draw a circuit diagram of an n-p-n transmitter with its emitter base function forward biased and base collector junction reverse biased. Describe briefly its properties (b) Explain how a transistor in active state exhibits a low resistance at its emitter base junction and high resistance at its base collector junction .

asked Jan 28, 2015 by meena.p

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a) Explain the formation of depletion layer and barrier potential in a P-n junction . (b) With the help of a labelled circuit diagram explain the use of P-n junction diode as a full wave rectifier. Draw the input and out put waveform

asked Jan 28, 2015 by meena.p

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a)Draw a ray diagram for formation of images of a point object by a thin double convex lens having radii of curvatures $R_1$ and $R_2$ and hence derive lens makers formula. b) Define power of a lens and give its S.I units . If a convex lens of length 50 cm is placed in contact coaxially with a concave lens of focal length 20 cm , what is the power of the combination ?

asked Jan 28, 2015 by meena.p

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An angular magnification (managing power) of 30 X is descibed using an objective of focal length $1.25\;cm$ and an eyepiece of focal length $5\;cm$ . how will you set up the compound microscope.

asked Jan 28, 2015 by meena.p

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(i)Draw the plot of binding energy per nuclear $\bigg(\large\frac{BE}{A}\bigg)$ as a function of man number A. Write two important conclusions that can be drawn regarding the nature of nuclear force. (ii) Use this graph to explain the release of energy in both processes of nuclear fusion and fission . (iii) write the basic nuclear process of neutron undergoing $\beta$- decay. Why is the detection of neutrical found very difficult ?

asked Jan 28, 2015 by meena.p

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Shreya's mother is diagnosed cancer. The attending physician suggested her for radiotherapy. He also highlighted the side effects of the treatment , also she will have t face a severe hairfall and may become bald. Shreya's mother after hearing their refused to take the treatment. (i) What would you do if you were in sherya's place? (ii) What values of life are associated with your attitude ? (iii) What are the types of radio active radiation ? Which one has the maximum penetrating power ?

asked Jan 28, 2015 by meena.p

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A long straight air- cored coil of length l has turns of radius R each . Obtain an expression for self induction of the coil.

asked Jan 28, 2015 by meena.p

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(i)How are eddy currents reduced in a metallic core ? (ii) give two uses of eddy current

asked Jan 28, 2015 by meena.p

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State kerchief's rules . How can you justify these rules ?

asked Jan 28, 2015 by meena.p

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Draw a plot showing the variation of photo electric current against the intensity of incident validation on a given photo sensitive surface.

asked Jan 28, 2015 by meena.p

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Monochromatic light of frequency $6.0 \times 10^{14}\;Hz$ is produced by a laser . The power emitted is $2.0 \times 10^{-3}\;Hz$ . Estimate the number of photos emitted per second one an average by the source.

asked Jan 28, 2015 by meena.p

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Derive an expression for the electric potential at a point along the axial line of an electric dipole.

asked Jan 28, 2015 by meena.p

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A square coil of side 10 m consists of $20$ turns and carries current of $12 A$ . The coil is suspended vertically and normal to the plane of the coil makes an angle of $30^{\circ}$ with the direction of a uniform horizontal magnetic field of magnitudes $0.80\;T$ . What is the magnitude of torque experience by the coil ?

asked Jan 28, 2015 by meena.p

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Using Biot - savart's law, derive an expression magnetic field at the center of a circular coil of radius r, having 'N' number of turns. Indicate the direction of the magnetic field.

asked Jan 28, 2015 by meena.p

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Sky waves are not used in transmitting the signals. Why ? State two factors by which the range of transmission of T.V signals can be increased.

asked Jan 28, 2015 by meena.p

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What is meant by interference of light? Write any two condition necessary for obtaining well defined and sustained interference pattern of light.

asked Jan 28, 2015 by meena.p

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Draw the logic circuit of a $NAND$ gate and wite its truth table.

asked Jan 28, 2015 by meena.p

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Which semiconductor her more mobility p- type or n-type ? Explain

asked Jan 28, 2015 by meena.p

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What are optical fibres ? give these applications of these fibres.

asked Jan 28, 2015 by meena.p

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The half life of $^{238}_{92} U$ against $\alpha$ decay is $1.5 \times 10^{17}\;s$ . What is the activity of a sample of $ ^{238}_{92}U$ having $25 \times 10^{20}$ atoms ?

asked Jan 28, 2015 by meena.p

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Show that the delay rate 'R' of a sample of a radio nuclei is related to the number of radio active nuclei 'N' at the same instant by the expression $R = \lambda N$

asked Jan 28, 2015 by meena.p

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A plane lamp placed $70\;cm$ from a screens one side produces the same illusion as a standard $60\; cd$ lamp placed $105\; cm$ away on other side of the screen. What is the deminous intensity of the first lamp ?

asked Jan 28, 2015 by meena.p

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For a single slit of width 'a', the first minutes of the inference pattern of a monochromatic light of wave length $\lambda$ occurs at an angle of $\large\frac{x}{a}$ . At the same angle of $\large\frac{\lambda}{a}$, we get a maximum for two narrow slits seperated by a distance 'a' Explain

asked Jan 28, 2015 by meena.p

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The half life of $^{90}_{30} sr$ is $28$ years. What is the disintegration rate of $15\;mg$ of their isotope ?

asked Jan 28, 2015 by meena.p

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For what kinetic energy of a neutron, will be associate by the de - Brogile wave length be $1.32\;kg$ given that mass of a $neutron = 1.675 \times 10^{-27}\;kg$

asked Jan 28, 2015 by meena.p

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Four hydrogen nuclei combine to form a helium nucleus, what amount of energy in mev will a released in this process?

asked Jan 28, 2015 by meena.p

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A cylindrical metallic wire is stretched to increase its length by $5\%$. Calculate the percentage change resistance.

asked Jan 28, 2015 by meena.p

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Find the difference of kinetic energies of photo electric emitted from a surface by light of wavelength $3000^{\circ} A$ and $1000^{\circ}A$

asked Jan 28, 2015 by meena.p

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What is the angle between the direction of electric field at any. (i) axial point and (ii) equatorial point due to an electrical dipole ?

asked Jan 28, 2015 by meena.p

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What is the angle between the direction of electric field at any. (i) axial point and (ii) equatorial point due to an electrical dipole ?

asked Jan 28, 2015 by meena.p

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State the relation between the frequency $\gamma$ of radiation emitted by LED and the band gap energy $E$ of the semiconductor used to fabricate it .

asked Jan 28, 2015 by meena.p

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What is the polarizing angle of medium of refractive index $1.732$?

asked Jan 28, 2015 by meena.p

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When we switch on an electric bulk, it almost lights up instantaneously through drift velocity of electron in copper wires is very small. give reason.

asked Jan 28, 2015 by meena.p

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Write the formula for magnetic moment of a current loop.

asked Jan 28, 2015 by meena.p

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Evaluate $I= \int \limits _0^{\large\frac{\pi}{2}} \large\frac{x}{\sin x +\cos x}$$dx$

asked Jan 23, 2015 by meena.p

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A wire of length $36\;cm$ is cut into two pieces. One of the pieces is turned in the form of a square and the other in the form of an equilateral triangle. Find the length of each piece so that the sum of the areas of the two be minimum.

asked Jan 23, 2015 by meena.p

1 answer

Make a rough sketch of the region given below and find its area using the method of integration $\{(x,y): 0 \leq y \leq x^2 +3, 0 \leq y \leq 2x+3,0 \leq x \leq 3 \}$

asked Jan 23, 2015 by meena.p

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Using integration find the area of the triangular region whose sides have the equation $y = 2x+1, y=3x+1,x=4$

asked Jan 23, 2015 by meena.p

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