Recent questions in JEEMAIN-2014

Amount of oxalic and present in a solution can be determined by its nitration with $kM_nO_4$ solution in the presence of $H_2SO_4$ . The nitration gives unsatisfactory result when carried out in the presence of Hcl because Hcl

asked Oct 4, 2018 by meena.p

1 answer

Two solutions of a substance are mixed in the following manner. $480 \;ml $ of $1.5\;M$ First solution +$520\;ml\;of\;1.2 M$ second solution . What is the molarity of the final mixture?

asked Aug 9, 2018 by meena.p

1 answer

Consider an ideal gas confined in an isolated closed chamber . As the gas undergoes an adiabatic expansion , the average time of collision between molecules increases as $V^{q}$, Where V is the volume of the gas . The value of q is : $\bigg(\gamma = \large\frac{C_p}{C_v}\bigg) $

asked Nov 12, 2015 by meena.p

1 answer

Two fixed friction less inclined plane making $30^{\circ}$ and $60^{\circ}$ with vertical are shown . Two blocks A and B are placed on the two planes . What is the relative vertical acceleration of a with respect to B.

asked May 13, 2015 by meena.p

1 answer

The time period of oscillation of a uniform rod with length l pivoted at one end is

asked May 13, 2015 by meena.p

1 answer

A jet of air moving with a speed of $50\;m/s$ with diameter $10\;mm$ strikes a disc kept vertical what is the force exerted by the air jet on the disc. (density of air $1.03\;kg/m^3)$

asked May 13, 2015 by meena.p

1 answer

If the radius of earth were increased by a factor of 2 keeping mass constant , by what factor would its density have to be changed to keep of the same .

asked May 12, 2015 by meena.p

1 answer

The coordinates of center of mass of uniform lamina shown in figure is

asked May 12, 2015 by meena.p

1 answer

A block of mass m is connected to a spring and passed over a pulley as shown in figure. The block is released from rest with the spring outstretched. Force constant of spring is k. Find the maximum extension in the spring .

asked May 12, 2015 by meena.p

1 answer

A object A is at a point $x=3\;m$ and $y= 1.25 \;m$ from a fixed point. At time $t=0$ the object starts moving with an acceleration of $1.5 \;m/s^2$ in the +ve x direction . At the same instant a stone is projected from origin with a velocity $\overrightarrow{u}$ and hits the object during its downward motions at an angle of $45^{\circ}$ to the horizontal. Find the time after which the store hots the object $[g= 10\;m/s^2]$

asked May 12, 2015 by meena.p

1 answer

One end of a copper rod of length 1 m and cross sectional area $4.0 \times 10^{-4} m^2$ is maintained at $100^{\circ}C$ At the other end of the ice is kept at $0^{\circ}C$.Neglecting loss of heat from surrounding the mass of ice melted in half hour is $[ K_{cu}=401 \;w/m k\;and\;L_f =3.35 \times 10^5 \;J/kg]$

asked May 12, 2015 by meena.p

1 answer

Two cars A and b are travelling in same direction with velocities $V_1$ and $V_2 (V_1 > V_2)$ when the car A is at a distance d ahead of car B , the driver of the car A applied the broke producing a uniform retardation a. There will be no collision when

asked May 12, 2015 by meena.p

1 answer

Two short magnets P and Q are arranged such that centres are on the x- axis and are separated by large distance the magnetic axis of P and Q are along X and Y axes respectively. At a point $R_1$ mid way between their centers , the magnitude of total induction at R due to both magnet is $ (if B is magnitude of induction due to a)

asked May 12, 2015 by meena.p

1 answer

A photo diode is made from a semiconductor with band gap of $2/5 \;eV$ , which of the following ranges of wavelength it can detected ?

asked May 12, 2015 by meena.p

1 answer

Two white point dots are 1 mm apart on a black paper. They are viewed by eye of pupil diameter 3 mm. Approximately what is the maximum distanceat which thes dots can be resolved by the eye (wave length of light = 500 nm)

asked May 12, 2015 by meena.p

1 answer

A prism is made of material of refractive index $\sqrt 3$. The angle of minimum derivation is equal to angle of prism, then the angle of prism is .

asked May 11, 2015 by meena.p

1 answer

Separation between plates of a parallel plate capacitors is 'd'. It is charged a battery then disconnected ,a dielectric slab of thickness $\large\frac{d}{3}$ and constant 3 is introduced in it . The fractional change in energy .

asked May 11, 2015 by meena.p

1 answer

If a photo cell is illuminated with a radiation of $1240 \;A^{\circ}$, the stopping potential is found to be $6V$ , then the work function of the emitter and the threshold wavelength are

asked May 11, 2015 by meena.p

1 answer

The magnetic field at O

asked May 11, 2015 by meena.p

1 answer

The radius of first orbit of hydrogen atom is $0.53 A^{\circ}$ and the electron is executing $6.54 \times 10^5 $ revolutions per second . The magnetic moment of electron will be

asked May 11, 2015 by meena.p

1 answer

In a PNP transistor working as a common base amplifier current gains $0.96$ and emitter current is $7.2 \;mA$ . The base current is

asked May 11, 2015 by meena.p

1 answer

The amount of active substance reduces to $ \large\frac{1}{64} $ of its initial value in 15 hours . What is the half life?

asked May 11, 2015 by meena.p

1 answer

At a temperature of $30^{\circ}$the susceptibility of a ferromagnetic material is found to be x. What is its susceptibility at $333^{\circ}$

asked May 11, 2015 by meena.p

1 answer

This is

asked May 11, 2015 by meena.p

1 answer

The electric field strength in an electro magnetic wave is $10^4 V/m$ The magnetic strength (in Tesla) is

asked May 11, 2015 by meena.p

1 answer

A negetively charged oil drop of mass $ 8 \times 10^{-15} \;kg$ remains suspended in a uniform field of $ 2\times 10^4 \;v/m$ in millikani experiment . The number of electrons making up the charge is $(g= 10\;m/s^2)$

asked May 11, 2015 by meena.p

1 answer

A box of mass $40\;kg$ is placed on an open truck . The coefficient of friction between the box and the surface of the truck is $0.15$ with what maximum acceleration can the truck move so that the box does not slide out.

asked May 11, 2015 by meena.p

1 answer

A car approaching a crossing at a speed of $20 \;m/s$ sounds a horn of frequency of $500\;hz$ . When the car is $80 \;m$ from the crossing. Speed of sound in air is $320\;m/s$ An observer is at a distance of $60\;m$ from the crossing on a road perpendicular to the direction of motion of car. What frequency is heard by the observer .

asked May 11, 2015 by meena.p

1 answer

The resistor in which maximum heat will be produced is

asked May 11, 2015 by meena.p

1 answer

plot the V-T graph corresponding to the P- T graph for a ideal gas shown in figure .

asked May 11, 2015 by meena.p

1 answer

Two thin lenses of same radius of curvature $R= 15\;cm$ of different nature made of different material one having refractive index $\mu_1 =\large\frac{2}{3}$ and another $\mu_2$ . The lenses are kept in contact and immersed in water of refractive index $\mu_w = \large\frac{3}{4}$. The focal length of the system of lenses in water is $30\;cm$ . What is the value of $\mu_2$

asked May 11, 2015 by meena.p

1 answer

A simple pendulum is suspended from ceiling of a lift. When the lift is at rest , its time period is $T_0$ with what acceleration should lift be acceleration upward in order to reduce it, time period to $T/2$?

asked May 11, 2015 by meena.p

1 answer

A uniform solid sphere is rotating with angular speed of $\omega_0$ about a diameter . The temperature of the solid is suddenly increased by $100^{\circ}$. What will be the new angular speed. $(\alpha = 3 \times 10^{-4}\;per ^{\circ}c)$

asked May 11, 2015 by meena.p

1 answer

Two circular plates of radius $5\;cm$ each , have a $0.01 \;mm$ thick water film between them . What will be the force required to separated the plates (surface tension of water = 73 dynes /cm)

asked Apr 30, 2015 by meena.p

1 answer

Two spheres of volume $500\;cc$ each of relative density $0.6$ and $1.2 $ are connected by string and the combination is immersed in a liquid. The tension in the string is

asked Apr 30, 2015 by meena.p

1 answer

In the circuit as shown in the figure what is the potential difference between P and Q.

asked Apr 30, 2015 by meena.p

1 answer

A disc is performing pure rolling on smooth stationary surface with constant angular velocity as shown. At any instant for the lower most point of the disc.

asked Apr 30, 2015 by meena.p

1 answer

A pendulum of mass $0.5 \;kg$ and length $1\;m$ is released from at an angle $\theta= 60^{\circ}$. What is the power delivered by all force acting on the bob at angle $\theta= 30^{\circ}(g= 10m/s^2)$

asked Apr 30, 2015 by meena.p

1 answer

A block is placed an a rough inclined plane at an angle of $45^{\circ}$. If the force needed to lift is greater than to drag it up along the inclined plane then the coefficient of friction $\mu $ must be

asked Apr 30, 2015 by meena.p

1 answer

A stone is projected at a certain angle. Two seconds before it reaches the maximum height it makes $60^{\circ}$with the horizontal.what is the velocity of the stone at highest point

asked Apr 30, 2015 by meena.p

1 answer

Displacement - time curve for a particle moving in a straight line is shown. Then

asked Apr 30, 2015 by meena.p

1 answer

The initial and final temperature of a liquid in a container are observed to be $75.3 \pm 0.4^{\circ}$ and $67.7 \pm 0.3^{\circ}C$. Find the fall in temperature

asked Apr 30, 2015 by meena.p

1 answer

Light rays of wave length $6000 A^{\circ}$ and photon intensity $39.6 \;W/m^2$ is incident on metal surface. If only $1 \%$ of photon incident on surface emit photo electrons, than the number of electrons omitted per second per unit area from the surface will be : $(h= 6.64 \times 10^{-34}$ Is ; $c= 3 \times 10^8 m/s)$

asked Apr 30, 2015 by meena.p

1 answer

Zn identical metal plates each of area A are placed parallel to each other, equal spiced at distance 'd' between neigh bouring plates. The plates are connected alternatily. The capacitance of the system is

asked Apr 30, 2015 by meena.p

1 answer

Zn identical metal plates each of area A are placed parallel to each other, equal spiced at distance 'd' between neigh bouring plates. The plates are connected alternatily. The capacitance of the system is

asked Apr 30, 2015 by meena.p

0 answers

A short linear object of length L lies on the axis of a spherical mirror of focal length f at a distance 'u' from the mirror. Its image has an axial length 'l' equal to

asked Apr 30, 2015 by meena.p

1 answer

Two concentric coils of 10 turns each are situated in the same plane. their radii are $20\;cm$ and $40\;cm$ , they carry $0.2\;A$ and $0.3\;a$ current respectively in opposite directions, the magnetic field(in tesla) at the centre is

asked Apr 30, 2015 by meena.p

1 answer

If two coherent source are placed at a distance $5 \lambda$ from each other symmetric to the center of the circle as shown in the figure, then the number of fingers shown on the screen placed along the circumference is

asked Apr 29, 2015 by meena.p

1 answer

Input is across A and C output is across B and D . then the output is

asked Apr 29, 2015 by meena.p

1 answer

A rectangular loop of length 'l' and breadth 'b' is placed at a distance of x from an infinity long wire carrying current i such that the direction of current is parallel to breadth. If the loop moves away from the current wire in a direction perpendicular to it with a velocity 'v', the magnitude of the emf in the loop is

asked Apr 29, 2015 by meena.p

1 answer

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