Recent questions in JEEMAIN-2014

If denote microwaves , X rays ,infrared ,gamma rays ,ultra - violet , radio waves and visible parts of the electromagnetic spectrum by M ,X,I,G,U,R and V , the following is the arrangement in ascending order of wavelength :

asked May 28, 2014 by yamini.v

0 answers

An example of a perfect diamagnet a superconductor .This implies that when a superconductor is put in a mangetic field of intensity B ,the magnetic field $\;B_{s}\;$ inside the superconductor will be such that :

asked May 28, 2014 by yamini.v

1 answer

A square frame of side 10 cm along straight wire carrying current 1 A are in the plane of the paper . Starting from close to the wire , the frame moves towards the right with a constant speed of $\;10\;ms^{-1}\;$ (see figure) .The e.m.f. induced at the time the left arm of the frame is at x=10 cm from the wire is :

asked May 28, 2014 by yamini.v

1 answer

Four bulbs $\;B_{1},B_{2},B_{3}\;$ and $\;B_{4}\;$ of 100 W each are connected to 220 V main as shown in the figure .The reading in an ideal ammeter will be :

asked May 28, 2014 by yamini.v

1 answer

The gap between the plates of a parallel plate capacitor of area A and distance between plates d , is filled with a dielectric whose permittivity varies linearly from $\;\in_{1}\;$ at one plate to $\;\in_{2}\;$ at the other .The capacitance of capacitor is :

asked May 28, 2014 by yamini.v

1 answer

The electric field in a region of space is given by ,$\;\overrightarrow{E}=E_{0} \hat{i}+ 2 E_{0} \hat{j}\;$ where$\;E_{0}=100\;N/C\;$.The flux of this field through a circular surface of radius 0.02 m parallel to the y - z plane is nearly :

asked May 28, 2014 by yamini.v

0 answers

The total length of a sonometer wire between fixed ends is 110 m .Two bridges are placed to divide the length of wire in ratio 6 :3 :2 .The tension in the wire is 400 N and the mass per unit length is 0.01 kg/m . What is the minimum common frequency with which three parts can vibrate ?

asked May 28, 2014 by yamini.v

0 answers

A body is in simple harmonic motion with time period half second (T=0.5 s) and amplitude one cm (A=1 cm).Find the average velocity in the interval in which it moves from equilibrium position to half of its amplitude .

asked May 28, 2014 by yamini.v

1 answer

A gas molecule of mass M at the surface of the Earth has kinetic energy equivalent at $\;0^{0}C\;$.If it were to go up straight without colliding with any other molecules , how height it would rise ? Assume that the height attained is much less than radius of the earth .($\;k_{B}\;$ is Boltzmann constant)

asked May 28, 2014 by yamini.v

0 answers

A gas is compressed from a volume of $\;2\;m^{3}\;$ to a volume of $\;1\;m^{3}\;$ at a constant pressure of $\;100\;N/m^{2}\;$.Then it is heated at constant volume by supplying 150 J of energy . As a result , the internal energy of the gas is :

asked May 28, 2014 by yamini.v

0 answers

A block coloured solid sphere of radius R and mass M is inside a cavity with vacuum inside .The walls of the cavity are maintained at temperature $\;T_{0}\;$ . The initial temperature of the sphere is $\;3T_{0}\;$.If the specific heat of the material of the sphere varies is $\;\alpha T^{3}\;$ per unit mass with the temperature T of the sphere , where $\;\alpha\;$ is a constant , then the time taken for the sphere to cool down to temperature $\;2T_{0}\;$ will be ($\;\sigma\; is stefan Boltzmann constant$

asked May 28, 2014 by yamini.v

1 answer

A large number of liquid drops each of radius r coalesce to from a single drop radius R.The energy released in the process is converted into kinetic energy of the big drop so formed . The speed of the big drop is (given surface tension of liquid T , density $\;\rho\;$)

asked May 28, 2014 by yamini.v

0 answers

In the diagram shown , the difference in the two tubes of the manometer is 5 cm ,the cross section of the tube at A and B is $\;6\;mm^{2}\;$ and $\;10\;mm^{2}\;$ respectively . The rate at which water flows through the tube is $\;(g=10\;ms^{-2})\;$

asked May 28, 2014 by yamini.v

1 answer

The velocity of water in a river is 18 km/hr near the surface . If the river is 5 m deep , find the shearing stress between the horizontal layers of water.The co - efficient of viscosity of water = $\;10^{-2}\;$ poise .

asked May 28, 2014 by yamini.v

0 answers

The gravitational field in a region is given by $\;\overrightarrow{g}=5\;N/kg\;\hat{i}+12\;N/kg\;\hat{j}\;$.The change in the gravitational potential energy of the particle of mass 2 kg when it is taken from the origin to a point (7m ,-3m) is :

asked May 28, 2014 by yamini.v

0 answers

A ball of mass 160 g is thrown up at an angle of $\;60^{0}\;$ to the horizontal at a speed of $\;10\;ms^{-1}\;$. the angular momentum of the ball at the highest point of the trajectory with respect to the point from which the ball is thrown is nearly $\;(g=10\;ms^{-2})\;$

asked May 28, 2014 by yamini.v

0 answers

A particle is released on a vertical smooth semicircular track from point X so that OX make angle $\;\theta\;$ from the vertical (see figure) .The normal reaction of the track on the particle vanishes at point Y where OY makes angle $\;\phi\;$ with the horizontal .Then :

asked May 28, 2014 by yamini.v

0 answers

Consider a cylinder of mass M resting on a rough horizontal rug that is pulled out from under it with acceleration ' a ' perpendicular to the axis of the cylinder .What is $\;F_{friction}\;$ at point P ? It is assumed that the cylinder does not slip .

asked May 28, 2014 by yamini.v

0 answers

A heavy box is to be dragged along a rough horizontal floor . To do so , person A pushes it at an angle $\;30^{0}\;$ from the horizontal and requires a minimum force $\;F_{A}\;$ , while person B pulls the box at an angle $\;60^{0}\;$ from the horizontal and needs minimum force $\;F_{B}\;$ . If the coefficient of friction between the box and the floor is $\;\large\frac{\sqrt{3}}{5}\;$, the ratio $\;\large\frac{F_{A}}{F_{B}}\;$ is :

asked May 28, 2014 by yamini.v

0 answers