Recent questions in JEEMAIN and NEET

Time taken by a 836 W heater to heat one litre of water from $10^{\circ}C$ to $40^{\circ}C$ is

asked Nov 5, 2018 by pady_1

0 answers

The thermistors are usually made of

asked Nov 5, 2018 by pady_1

0 answers

In a metre bridge experiment null point is obtained at 20 cm from one end of the wire when resistance X is balanced against another resistance Y. If X < Y, then where will be the new position of the null point from the same end, if one decides to balance a resistance of 4X against Y?

asked Nov 5, 2018 by pady_1

0 answers

An electric current is passed through a circuit containing two wires of the same material, connected in parallel. If the length and radii of the wires are in the ratio of 4/3 and 2/3, then the ratio of the currents passing through the wire will be

asked Nov 5, 2018 by pady_1

0 answers

The resistance of the series combination of two resistances is S. When they are joined in parallel through total resistance is P. If $S=nP$, then the minimum possible value of n is

asked Nov 5, 2018 by pady_1

0 answers

The total current supplied to the circuit by the battery is

asked Nov 5, 2018 by pady_1

0 answers

Alternating current can not be measured by D.C. ammeter because

asked Nov 5, 2018 by pady_1

0 answers

Four charges equal to -Q are placed at the four corners of a square and a charge q is at its centre. If the system is in equilibrium the value of q is

asked Nov 5, 2018 by pady_1

0 answers

A charged particle q is shot towards another charged particle Q which is fixed, with a speed v it approaches Q upto a closest distance r and then returns. If q were given a speed 2v, the closest distances of approach would be

asked Nov 5, 2018 by pady_1

0 answers

Two spherical conductor B and C having equal radii and carrying equal charges in them repel each other with a force F when kept apart at some distance. A third spherical conductor having same radius as that of B but uncharged brought in contact with B, then brought in contact with C and finally removed away from both. The new force of repulsion, between B and C is

asked Nov 5, 2018 by pady_1

0 answers

An electromagnetic wave of frequency $v =3.0 \;MHz$ passes from vacuum into a dielectric medium with permittivity $\varepsilon = 4.0$. Then

asked Nov 5, 2018 by pady_1

0 answers

The maximum number of possible interference maxima for slit-separation equal to twice the wavelength in Young's double-slit experiment is

asked Nov 5, 2018 by pady_1

2 answers

The angle of incidence at which reflected light totally polarized for reflection from air to glass (refractive index n), is

asked Nov 5, 2018 by pady_1

0 answers

A plane convex lens of refractive index 1.5 and radius of curvature 30 cm is silvered at the curved surface. Now this lens has been used to form the image of an object. At what distance from this lens an object be placed in order to have a real image of the size of the object ?

asked Nov 5, 2018 by pady_1

0 answers

A light ray is incident perpendicular to one face of a $90^{\circ}$ prism and is totally internally reflected at the glass-air interface. If the angle of reflection is $45^{\circ}$, we conclude that the refractive index $n$

asked Nov 5, 2018 by pady_1

0 answers

The temperature of two outer surface of a composite slab, consisting of two materials having coefficients of thermal conductivity $K$ and $2K$ and thickness $x$ and $4x$, respectively are $T_2$ and $T_1 (T_2> T_1)$. The rate of heat tranfer through the slab, in a steady state is $(\frac{A(T_2 - T_1) K}{x})f$, with $f$ equal to

asked Nov 5, 2018 by pady_1

0 answers

A radiation of energy E falls normally on a perfectly reflecting surface. The momentum transferred to the surface is

asked Nov 5, 2018 by pady_1

0 answers

Two thermally insulated vessels 1 and 2 are filled with air at temperatures $(T_1, \; T_2)$, volume $(V_1, \; V_2)$ and pressure $(P_1, \; P_2)$ respectively. If the value joining two vessels is opened, the temperature inside the vessel at equilibrium will be

asked Nov 5, 2018 by pady_1

0 answers

Which of the following statements is correct for any thermodynamic system ?

asked Nov 5, 2018 by pady_1

1 answer

If the temperature of the Sun were to increase from $T$ to $2T$ and its radius from $R$ to $2R$, then the ratio of the radiant energy received on earth to what it was previously will be

asked Nov 5, 2018 by pady_1

0 answers

One mole of ideal monoatomic gas $(\gamma = 5/30)$ is mixed with one mole of diatomic gas $(\gamma = 7/5)$. What is $\gamma$ for the mixture ? $\gamma$ denotes the ratio of specific heat at constant pressure, to that at constant volume.

asked Nov 5, 2018 by pady_1

0 answers

In forced oscillation of a particle the amplitude is maximum frequency $\omega_1$ of the force, while the energy is maximum for a frequency $\omega_2$ of the force, then

asked Nov 5, 2018 by pady_1

1 answer

A particle of mass $m$ is attached to a spring (of spring constant $k$) and has a natural angular frequency $\omega_0$. An external force $F(t)$ proportional to $\cos \omega t ( \omega \neq \omega_0)$ is applied to the oscillator. The time displacement of the oscillator will be proportional to

asked Nov 5, 2018 by pady_1

0 answers

The displacement $y$ of a particle in a medium can be expressed as $y = 10^{-6} \sin (110 t + 20 x + \pi/4)\;m$ where $t$ is in seconds and $x$ in meter. The speed of the wave is

asked Nov 5, 2018 by pady_1

0 answers

The total energy of particle, executing simple harmonic motion is

asked Nov 5, 2018 by pady_1

0 answers

A particle at the end of a spring executes simple harmonic motion with a period $t_1$, while the corresponding period for another spring is $t_2$. If the period of oscillation with the two springs in series is $t$, then

asked Nov 5, 2018 by pady_1

0 answers

The bob of a simple pendulum executes simple harmonic motion in water with a period $t$, while the period of oscillation of the bob is $t_0$ is air. Neglecting frictional force of water and given that the density of the bob is $(\frac{4}{3}) \times 1000\; kg/m^3$. What relationship between $t$ and $t_0$ is true ?

asked Nov 5, 2018 by pady_1

0 answers

If two soap bubbles of different radii are connected by a tube,

asked Nov 5, 2018 by pady_1

0 answers

Spherical balls of radius R are falling in a viscous fliud of viscosity $\eta$ with a velocity v. The retarding viscous force acting on the spherical ball is

asked Nov 5, 2018 by pady_1

0 answers

A wire fixed at the upper end stretches by length $\ell$ by applying a force $F$. The work done in stretching is

asked Nov 5, 2018 by pady_1

0 answers

Suppose the gravitational force varies inversely as the $n^{th}$ power of distance. Then the time period planet in circular orbit of radius $R$ around the sun will be proportional to

asked Nov 5, 2018 by pady_1

1 answer

If $g$ is the acceleration due to gravity on the earth's surface, the gain in the potential energy of object of mass $m$ raised from the surface of the earth to a height equal to the radius $R$ of the earth is

asked Nov 5, 2018 by pady_1

0 answers

The time period of an earth satellite in circular orbit is independent of

asked Nov 5, 2018 by pady_1

0 answers

A satellite of mass $m$ revolves around the earth of radius $R$ at a height $x$ from its surface. If $g$ is the acceleration due to gravity on the surface of the earth, the orbital speed of the satellite is

asked Nov 5, 2018 by pady_1

0 answers

One solid sphere A and another hollow sphere B are of same mass and same outer radii. Their moment of inertia about their diameters are respectively $I_A$ and $I_B$ such that where $d_A$ and $d_B$ are their densities.

asked Nov 5, 2018 by pady_1

0 answers

A ball is thrown from a point with a speed $v_{_0}$ at an angle of projection $\theta$. From the same point and at the same instant person starts running with a constant speed $v_{_0}/2$ to catch the ball. Will the person be able to catch the ball ? If yes, what should be the angle of projection ?

asked Nov 5, 2018 by pady_1

0 answers

A solid sphere is rotating in free space. If the radius of the sphere is increased keeping mass same which one of the following will not be affected ?

asked Nov 5, 2018 by pady_1

0 answers

A particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of the particle, the motion of the particle takes place in a plane. It follows that

asked Nov 5, 2018 by pady_1

0 answers

A body of mass $m$, accelerates uniformly from rest to $v_1$ in time $t_1$. The instantaneous power delivered to the body as a function of time $t$ is

asked Nov 5, 2018 by pady_1

0 answers

A force $\overrightarrow{F} = (5\hat{i} +3 \hat{j} +2 \hat {k})N$ is applied over a particle which displaces it from its origin to the point $\overrightarrow{r} = (2 \hat{i} - \hat{j})m$. The work done on the particle in joules is

asked Nov 5, 2018 by pady_1

0 answers

A block rests on a rough inclined plane making an angle of $30^{\circ} $ with the horizontal. The coefficient of static friction between the block and the plane is $0.8$. If the frictional force on the block is $10\; N$, the mass of the mass of the block (in kg) is (take $g=10\;m/s^2$)

asked Nov 5, 2018 by pady_1

1 answer

A uniform chain of length $2\; m$ is kept on a table such that a length of $60\; cm$ hangs freely from the edge of the table. The total mass of the chain is $4\; kg$. What is the work done in pulling the entire chain on the table?

asked Nov 5, 2018 by pady_1

0 answers

Two masses $m_1 = 5\; kg$ and $m_2 = 4.8 \; kg$ tied to a string are hanging over a light frictionless pulley. What is the acceleration of the masses when light free to move ? ($g = 9.8\; m/s^2$)

asked Nov 5, 2018 by pady_1

0 answers

A machine gun fires bullet of mass $40\;g$ with a velocity $1200\;ms^{-1}$. The man holding it can exert a maximum force of $144\;N$ on the gun. How many bullets can he fire per second at the most ?

asked Nov 5, 2018 by pady_1

0 answers

An automobile travelling with speed of $60\; km/h$, can brake to stop within a distance of 20 cm. If the car is going twice as fast, i.e $120\; km/h$, the stopping distance will be

asked Nov 5, 2018 by pady_1

0 answers

Which of the followng statements is false for a particle moving in a circle with a constant angular speed ?

asked Nov 5, 2018 by pady_1

0 answers

A projectile can have the same range R for two angles of projection. If $T_1$ and $T_2$ be the time of flights in the two cases, then the product of the two time of flights is directly proportional to

asked Nov 5, 2018 by pady_1

0 answers

If $\overrightarrow{A} \times \overrightarrow{B} = \overrightarrow{B} \times \overrightarrow{A}$, then the angle between $A$ and $B$ is

asked Nov 5, 2018 by pady_1

0 answers

A ball is released from the top of a tower of height $h$ metres. It takes $T$ seconds to reach the ground. What is the position of the ball in $T/3$ seconds ?

asked Nov 5, 2018 by pady_1

0 answers

A particle moves in a straight line with retardation proportional to its displacement. Its loss of kinetic energy for any displacement $x$ is proportional to

asked Nov 5, 2018 by pady_1

0 answers

Ask Questions, Get Answers