Recent questions tagged jeemain

A particle of mass $1 \times 10^{-26}\;kg$ and charge $1.6 \times 10^{-19} C$ travelling with a velocity $1.28 \times 10^{6} ms^{-1}$ along the positive X-axis enters a region in which a uniform electric field $\overrightarrow {E} $ and a uniform magnetic field of induction $\overrightarrow {B}$ are present. If $\overrightarrow {E} =-102.4 \times 10^3 \hat k NC^{-1}$ and $B= 8 \times 10^{-2}\; \hat j Wbm^{-2}$, the direction of motion of the particles is :

asked Nov 8, 2013 by meena.p

1 answer

According to Moseley's law, the frequency (v) of the $K_{\alpha}$ line and the atomic number Z of the element have the relation (A and B are constants);

asked Nov 8, 2013 by meena.p

0 answers

Magnetic field induction at the center of a circular coil of radius 5 cm and carrying a current 0.9 A is (in SI units) ($\in _0$= absolute permittivity of air in SI units, velocity of light $= 3 \times 10^8 ms^{-1})$

asked Nov 8, 2013 by meena.p

1 answer

Two parallel rails of a railway track insulated from each other and with the ground are connected to a millivoltmeter. The distance between the rails is one meter. A train is travelling with a velocity of 72 km/h along the track. The reading of the millivoltmeter (in mV) is : (Vertical component of the earth's magnetic induction is $2 \times 10^{-5} T)$

asked Nov 8, 2013 by meena.p

1 answer

An inductance 1 H is connected in series with an AC source of 220 V and 50Hz. The inductive reactance (in ohms) is :

asked Nov 8, 2013 by meena.p

1 answer

Consider the following statements A and B and identify the correct answers given below: A: Peltier coefficient is numerically equal to the potential difference across the junctions of the thermonuclear through which current is flowing. B:According to Thomson, energy is neither absorbed nor evelved at the junction of a thermocouple but is observed or evolved only along the lengths of both the conductors.

asked Nov 8, 2013 by meena.p

1 answer

In a meter bridge a $30\;\Omega$ resistance is connected in the left gap and a pair of resistances P and Q in the right gap. Measured from the left, the balance point is 37.5 cm , when P and Q are in series and $71.4\;cm$ when they the parallel. The values of P and Q (in $\Omega$) are :

asked Nov 8, 2013 by meena.p

1 answer

A 6 V cell with $0.5 \Omega$ internal resistance, a 10 V cell with $1 \Omega$ internal resistance and a $12 \Omega$ external resistance are connected in parallel. The current (in ampere) through the 10 V cell is :

asked Nov 8, 2013 by meena.p

1 answer

Two charges 2 C and 6C are separated by a finite distance. If a charge of $-4C$ is added to each of them, the initial force of $12 \times 10^3\;N$ will change to :

asked Nov 7, 2013 by meena.p

1 answer

The vector that makes equal angle with $\large\frac{1}{3}$$(\hat i-2\hat j+2\hat k), \:\large\frac{1}{5}$$(-4\hat i-3\hat k)$ and $\hat j$ is ?

asked Nov 7, 2013 by rvidyagovindarajan_1

1 answer

A 4 $\mu F$ capacitor is charged by a 200 V battery. It is then disconnected from the supply and is connected to another uncharged $2\; \mu F$ capacitor. During the process, loss of energy (in J) is :

asked Nov 7, 2013 by meena.p

1 answer

If two identical bar magnets, each of length l, pole strength m, and magnetic moment M are placed perpendicular to each other with their unlike poles in contact, the magnetic moment of the combination is :

asked Nov 7, 2013 by meena.p

1 answer

With a standard rectangular bar magnet of length (l), breath (b ; b < < l) and magnetic moment M, the time period of the magnet in a vibration magnetometer is 4 s. If the magnet is cut normal to its length into four equal pieces, the time period (in seconds) with one of the pieces is :

asked Nov 7, 2013 by meena.p

1 answer

A light ray of wavelength $ \lambda$ is passing through a pin hole of diameter D and the effect is observed on a screen placed at a distance L from the pin hole. The approximations of geometrical optics are applicable if :

asked Nov 7, 2013 by meena.p

1 answer

Fraunhofer lines are produced by the absorption of light in :

asked Nov 7, 2013 by meena.p

0 answers

The focal length of an equi-convex lens is greater than the radius of curvature of any of the surfaces. Then the refractive index of the material of the lens is :

asked Nov 7, 2013 by meena.p

1 answer

Assertion (A) :Propagation of light through an option fibre is due to total internal reflection taking place place at the core-clad interface. Reason (R): Refractive index of the material of the core of the optical fibre is greater than that of air .

asked Nov 7, 2013 by meena.p

0 answers

A transverse wave propagating on a stretched string of linear density $3 \times 10^{-4}\;kg-m^{-1}$ is represented by the equation $y=0.2 \sin (15 x +60 l)$ where x is in meters and l is in seconds . The tension in the string (in newton) is :

asked Nov 7, 2013 by meena.p

1 answer

A vehicle sounding a whistle of frequency 256 Hz is moving on a straight road, towards a hill with a velocity of $10\;ms^{-1}$. The number of beats per second observed by a person travelling in the vehicle is : (Velocity of sound=330 \;ms^{-1})

asked Nov 7, 2013 by meena.p

1 answer

Two identical bodies have temperatures $277^{\circ}C $ and $67^{\circ}C$. If the surroundings temperature is $27^{\circ}C$, the ratio of loss of heats of the two bodies during the same interval of time is (approximately) :

asked Nov 7, 2013 by meena.p

1 answer

The tyre of a motor car contains air at $15^{\circ}C$. If the temperature increases to $35^{\circ}C$ the approximate percentage increase in pressure is (ignore to expansion of tyre):

asked Nov 7, 2013 by meena.p

1 answer

The ratio of specific heats of a gas is $ \gamma$. The change in internal energy of one mole of the gas, when the volume changes from V to 2V at constant pressure P is :

asked Nov 7, 2013 by meena.p

1 answer

The relation between the coefficient of real expansion $(\gamma_r)$ and coefficient of apparent expansion $(\gamma _a)$ of a liquid and the coefficient of linear expansion $(\alpha _g)$ of the material of the container is :

asked Nov 7, 2013 by meena.p

1 answer

An iron sphere of mass $20 \times 10^{-3}\;kg$ falls through a viscous liquid with terminal velocity $0.5\;ms^{-1}.$ The terminal velocity $(in\; ms^{-1})$ of another iron sphere of mass $54 \times 10^{-2}\;kg$ is :

asked Nov 7, 2013 by meena.p

1 answer

The heat evolved for the rise of water when one end of the capillary tube of radius r is immersed vertically into water is : (Assume surface tension=T and density of water to be p)

asked Nov 7, 2013 by meena.p

1 answer

The radii and Young's moduli of two uniform wires A and B are in the ratio 2: 1 and 1:2 respectively. Both wires are subjected to the same longitudinal force. If the increase in length of the wire A is one percent, the percentage in length of the wire B is :

asked Nov 7, 2013 by meena.p

1 answer

A body of mass m is is suspended to an ideal spring of force constant k. The expected change in the position force F acting vertically downwards is :

asked Nov 7, 2013 by meena.p

1 answer

Degenerate electron pressure will not be sufficient to prevent core collapse of white dwarf if its mass becomes n times of solar mass. Value of n is :

asked Nov 7, 2013 by meena.p

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Identify the increasing order of the angular velocities of the following :

asked Nov 7, 2013 by meena.p

1 answer

The instantaneous velocity of a point B of the given rod of length 0.5 m is 3 m/s in the represented direction. The angular velocity of the rod for the minimum velocity of end A is

asked Nov 7, 2013 by meena.p

1 answer

The minimum force required to move a body up an inclined plane is three times the minimum force required to prevent it from sliding down the plane. If the coefficient of friction between the body and the inclined plane is $\large\frac{1}{2 \sqrt 3},$ the angle of the inclined plane is :

asked Nov 7, 2013 by meena.p

1 answer

Consider the following statements A and B and identify the correct answer: (A): In an elastic collision , if a body suffers a head on collision with another of same mass at rest, the first body comes to rest while the other starts moving with the velocity of the first one . (B): Two bodies of equal mass suffering a head on elastic collision merely exchanges their velcities :

asked Nov 7, 2013 by meena.p

1 answer

The center of mass of three particles of masses 1 kg,2 kg and 3 kg is at (2,2,2). The position of the fourth mass of 4 kg to be placed in the system as that the new center of mass is at (0,0,0) is :

asked Nov 7, 2013 by meena.p

2 answers

The machine gun fires 240 bullets per minute. If the mass of each bullet is 10 g and the velocity of the bullets is $600\; ms^{-1}$ the power (in kW) of the gun is :

asked Nov 7, 2013 by meena.p

1 answer

The equation of trajectory of a projectile is $y= 10 x - \bigg(\large\frac{5}{9} \bigg)x^2$. If we assume $g=10\;ms^{-2},$ the range of projectile (in meter) is :

asked Nov 7, 2013 by meena.p

0 answers

The equation of trajectory of a projectile is $y=10x-\bigg(\large\frac{5}{9}\bigg)x^2$. If we assume $g=10\;ms^{-2}, the range of projectile (in metre) is :

asked Nov 7, 2013 by meena.p

0 answers

A body projected vertically upwards crosses a point twice in its journey at a height h just after $t_1$ and $t_2$ seconds. Maximum height reached by the body is :

asked Nov 7, 2013 by meena.p

1 answer

At a given instant of time the position vector of a particle moving in a circle with a velocity $3 \hat i- 4 \hat j + 5 \hat k$ is $\hat i+9 \hat j -3 \hat k$. Its angular velocity at that time is :

asked Nov 7, 2013 by meena.p

1 answer

Names of units of some physical quantities are given in List I and their dimensions formulae are given in List- II. Match the correct pairs in the lists:

asked Nov 7, 2013 by meena.p

1 answer

The solution of $\large\frac{dx}{dy}+\frac{x}{y}$$=x^2$ is :

asked Nov 7, 2013 by meena.p

1 answer

The solution of $(1+x^2) \large\frac{dy}{dx}$$+2xy-4x^2=0$ is :

asked Nov 7, 2013 by meena.p

1 answer

The solution of $(x^2+y^2)dx =2xy \;dy$ is :

asked Nov 7, 2013 by meena.p

1 answer

$\int _{-1} ^ 1 \large\frac{\cos h x }{1+e^{2x}}$$dx$ is equal to :

asked Nov 7, 2013 by meena.p

1 answer

$\int \limits_0^{\pi/2} \large\frac{dx}{1+ \tan^3 x}$ is equal to :

asked Nov 7, 2013 by meena.p

1 answer

Dividing the interval [0,6] into 6 equal parts and by using trapezoidal rule the value of $\int \limits_0^6 x^3 dx$ is approximately:

asked Nov 7, 2013 by meena.p

1 answer

Observe the following statements : $A : \int \bigg(\large\frac { x^2-1}{x^2} \bigg)e. ^{\large\frac{x^2-1}{x}}\; dx= e^{\large\frac{x^2-1}{x}}+c.$$\qquad R:\int f'(x)e^{f(x)}dx=f(x)+c.$ Then which of the following is true ?

asked Nov 7, 2013 by meena.p

1 answer

If $\int \large\frac{dx}{x^2+2x+2}$$=f(x) +c,$ then f(x) is equal

asked Nov 7, 2013 by meena.p

1 answer

If $\int \sqrt {\large\frac{x}{a^3-x^3}}dx=g(x)+c,$ then $g(x) $ is equal to :

asked Nov 7, 2013 by meena.p

1 answer

The set of all possible values of $'c'$ for which $\overrightarrow a=c \log_3 x\hat i-6\hat j+3\hat k$ and $\overrightarrow b=\log_3x\hat i+2\hat j+2c\log_3x\hat k$ making acute angle for $\forall x\in (0,\infty)$ is ?

asked Nov 6, 2013 by rvidyagovindarajan_1

1 answer

In a rt. angled $\Delta$ $ABC$, the hypotenuse $|\overrightarrow {AB}|=p$,then $\overrightarrow {AB}.\overrightarrow {AC}+\overrightarrow {BC}.\overrightarrow {BA}+\overrightarrow {CA}.\overrightarrow {CB}=?$

asked Nov 6, 2013 by rvidyagovindarajan_1

1 answer

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