Recent questions tagged neet

A reaction having equal energies of activation for forward and reverse reactions has -

asked Aug 20, 2018 by pady_1

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A hydrogen gas electrode is made by dipping platinum wire in a solution of HCl of pH = 10 and by passing hydrogen gas around the platinum wire at one atm pressure. The oxidation potential of electrode would be ?

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What is the activation energy for a reaction if its rate doubles when the temperature is raised from $20^oC$ to $35^oC$ ? (R = 8.314 $J mol^{-1} K^{-1}$)

asked Aug 20, 2018 by pady_1

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What is the maximum numbers of electrons that can be associated with the following set of quantum numbers ? n = 3, l = 1 and m = -1

asked Aug 20, 2018 by pady_1

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The value of Planck's constant is $6.63 \times 10^{-34} Js$. The speed of light is $3 \times 10^{17} nms^{-1}$. Which value is closest to the wavelength in nanometer of a quantum of light with frequency of $6 \times 10^{15} s^{-1}$ ?

asked Aug 20, 2018 by pady_1

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The output (X) of the logic circuit shown in figure will be -

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In a common emitter (CE) amplifier having a voltage gain G, the transistor used has transconductance 0.03 mho and current gain 25. If the above transistor is replaced with another one with transconductance 0.02 mho and current gain 20, the voltage gain will be -

asked Aug 20, 2018 by pady_1

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In a n-type semiconductor, which of the following statements is true -

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A parallel beam of fast moving electrons is incident normally on a narrow slit. A fluorescent screen is placed at a large distance from the slit. If the speed of the electrons is increased, which of the following statements is correct ?

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In Young’s double slit experiment, the slits are 2mm apart and are illuminated by photons of two wavelengths $\lambda_1 = 12000 Å$ and $\lambda_2 = 10000 Å$. At what minimum distance from the common central bright fringe on the screen 2m from the slit will a bright fringe from one interference pattern coincide with a bright fringe from the other ?

asked Aug 20, 2018 by pady_1

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For a normal eye, the cornea of eye provides a converging power of 40D and the least converging power of the eye lens behind the cornea is 20D. Using this information, the distance between the retina and the corneaeye lens can be estimated to be -

asked Aug 20, 2018 by pady_1

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A plano convex lens fits exactly into a plano concave lens. Their plane surfaces are parallel to each other. If lenses are made of different materials of refractive indices $\mu_1$ and $\mu_2$ and R is the radius of curvature of the curved surface of the lenses, then the focal length of the combination is -

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The wavelength $\lambda_e$ of an electron and $\lambda_p$ of a photon of same energy E are related by -

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For photoelectric emission from certain metal the cutoff frequency is $ν$. If radiation of frequency $2ν$ impinges on the metal plate, the maximum possible velocity of the emitted electron will be (m is the electron mass) -

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A certain mass of Hydrogen is changed to Helium by the process of fusion. The mass defect in fusion reaction is 0.02866 u. The energy liberated per u is – (Given 1 u = 931 MeV)

asked Aug 20, 2018 by pady_1

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The half-life of a radioactive isotope ‘X’ is 20 years. It decays to another element ‘Y’ which is stable. The two elements ‘X’ and ‘Y’ were found to be in the ratio 1 : 7 in a sample of a given rock. The age of the rock is estimated to be -

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Ratio of longest wave lengths corresponding to Lyman and Balmer series in hydrogen spectrum is -

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The condition under which a microwave oven heats up a food item containing water molecules most efficiently is -

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A coil of self-inductance L is connected in series with a bulb B and an AC source. Brightness of the bulb decreases when -

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A wire loop is rotated in a magnetic field. The frequency of change of direction of the induced e.m.f. is -

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A bar magnet of length â€˜lâ€™ and magnetic dipole moment â€˜Mâ€™ is bent in the form of an arc as shown in figure. The new magnetic dipole moment will be â€“

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1 answer

A current loop in a magnetic field -

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When a proton is released from rest in a room, it starts with an initial acceleration $a_0$ towards west. When it is projected towards north with a speed $v_0$ it moves with an initial acceleration $3a_0$ toward west. The electric and magnetic fields in the room are -

asked Aug 20, 2018 by pady_1

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The resistances of the four arms P, Q, R and S in a Wheatstone’s bridge are 10 ohm, 30 ohm, 30 ohm and 90 ohm, respectively. The e.m.f. and internal resistance of the cell are 7 volt and 5 ohm respectively. If the galvanometer resistance is 50 ohm, the current drawn from the cell will be -

asked Aug 20, 2018 by pady_1

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The internal resistance of a 2.1 V cell which gives a current of 0.2A through a resistance of $10 \Omega$ is -

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A wire of resistance 4Ω is stretched to twice its original length. The resistance of stretched wire would be -

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A, B and C are three points in a uniform electric field. The electric potential is -

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Two pith balls carrying equal charges are suspended from a common point by strings of equal length, the equilibrium separation between them is r. Now the strings are rigidly clamped at half the height. The equilibrium separation between the balls now become -

asked Aug 20, 2018 by pady_1

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A source of unknown frequency gives 4 beats/s, when sounded with a source of known frequency 250 Hz. The second harmonic of the source of unknown frequency gives five beats per second, when sounded with a source of frequency 513 Hz. The unknown frequency is -

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It we study the vibration of a pipe open at both ends, then the following statement is not true -

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A wave travelling in the +ve x-direction having displacement along y-direction as 1m, wavelength $2 \pi m$ and frequency of $\frac{1}{\pi}$ Hz is represented by :

asked Aug 20, 2018 by pady_1

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The amount of heat energy required to raise the temperature of 1 g of Helium at NTP, from $T_1 \; K$ to $T_2 \; K$ is :

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In the given $(V-T)$ diagram, what is the relation between pressures $P_1$ and $P_2$ ?

asked Aug 20, 2018 by pady_1

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During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its temperature. The ratio of $\frac{C_p}{C_v}$ for the gas is -

asked Aug 20, 2018 by pady_1

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A gas is taken through the cycle $A \to B \to C \to A$, as shown. What is the net work done by the gas ?

asked Aug 20, 2018 by pady_1

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A piece of iron is heated in a flame. It first becomes dull red then becomes reddish yellow and finally turns to white hot. The correct explanation for the above observation is possible by using -

asked Aug 20, 2018 by pady_1

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The molar specific heats of an ideal gas at constant pressure and volume are denoted by $C_p$ and $C_v$, respectively. If $\gamma = \frac{C_p}{C_v}$ and R is the universal gas constant, then $C_v$ is equal to -

asked Aug 20, 2018 by pady_1

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The wettability of a surface by a liquid depends primarily on -

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The following four wires are made of the same material. Which of these will have the largest extension when the same tension is applied ?

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Infinite number of bodies, each of mass 2 kg are situated on x-axis at distances 1m, 2m, 4m, 8m, … , respectively, from the origin. The resulting gravitational potential due to this system at the origin will be -

asked Aug 20, 2018 by pady_1

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A body of mass 'm' is taken from the earth's surface to the height equal to twice the radius (R) of the earth. The change in potential energy of body will be -

asked Aug 20, 2018 by pady_1

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A small object of uniform rolls up a curved surface with an initially velocity 'v'. It reaches upto a maximum height of $\frac{3v^2}{4g}$ with respect to the initial position. The object is -

asked Aug 20, 2018 by pady_1

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A rod PQ of mass M and length L is hinged at end P. The rod is kept horizontal by a massless string tied to point Q as shown in figure. When string is cut, the initial angular acceleration of the rod is -

asked Aug 20, 2018 by pady_1

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An explosion breaks a rock into three parts in a horizontal plane. Two of them go off at right angles to each other. The first part of mass 1 kg moves with a speed of $12 ms^{–1}$ and the second part of mass 2 kg moves with $8 ms^{–1}$ speed. If the third part files off with $4 ms^{–1}$ speed, then its mass is -

asked Aug 20, 2018 by pady_1

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A uniform force of $(3 \hat{i} + \hat {j})$ newton acts on a particle of mass 2 kg. Hence the particle is displaced from position $(2 \hat {i} + \hat{k})$ meter to position $(4 \hat{i} + 3 \hat{j} - \hat{k})$ meter. The work done by the force on the particle is -

asked Aug 20, 2018 by pady_1

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The upper half of an inclined plane of inclination θ is perfectly smooth while lower half is rough. A block starting from rest at the top of the plane will again come to rest at the bottom, if the coefficient of friction between the block and lower half of the plane is given by -

asked Aug 20, 2018 by pady_1

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Three blocks with masses m, 2m and 3m are connected by strings, as shown in the figure. After an upward force F is applied on block m, the masses move upward at constant speed v. What is the net force on the block of mass 2m ? (g is the acceleration due to gravity)

asked Aug 20, 2018 by pady_1

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A stone falls freely under gravity. It covers distances $h_1$, $h_2$ and $h_3$ in the first 5 seconds, the next 5 seconds and the next 5 seconds respectively. The relation between $h_1$, $h_2$ and $h_3$ is -

asked Aug 20, 2018 by pady_1

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The velocity of a projectile at the initial point A is $(2 \hat{i} + 3 \hat{j})$ m/s. It's velocity (in m/s) at point B is -

asked Aug 20, 2018 by pady_1

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In an experiment four quantities a, b, c and d are measured with percentage error 1%, 2%, 3% and 4% respectively. Quantity P is calculated as follows : $P = \frac{a^3b^2}{cd} . \%$ error in P is :

asked Aug 20, 2018 by pady_1

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