Explore topic-wise InterviewSolutions in .

A train is travelling at the speed of 180 km/hr. In order to trap superman Lex Luthor has broken the tracks. Unware of Luthor's evil intensions, superman tries to stop the train by pushing it in opposite direction.Right at the moment when the train is 300 m away from the crack in the track, Superman is applying a deceleration of 5 m/$s^2$. Just after 2 sec a bullet laced with kryptonite hits superman which incapacitates him for a while. How long has super man got to remove the bullet and start to give deceleration so to protect the innocents? (Trains brake system has failed)

question

A plate composed of welded sheets of aluminum and iron is connected to an electric circuit . What will happen if fairly strong current is passed through the circuit . Where will the strip bend and why?

Two horizontal parallel straight conductors, each $20\text{cm}$ long, are arranged one vertically above the other and carry equal currents in opposite directions. The lower conductor is fixed while the other is free to move in vertical plane remaining parallel to the lower. If the upper conductor weights $1.20\text{g}$, what is the approximate current that will maintain the conductors at a distance $0.75\text{cm}$ apart. (Given : $g=9.8{\text{m/s}}^2$)

The fractional change in the value of free-fall acceleration 'g' for a particle when it is lifted from the surface to an elevation h (h<<R) is

A car moves on a horizontal track of radius $r$, the speed is increasing at a constant rate $a$, coefficient of friction between road and tyre is $\mu ,$ the speed at which car will skid is

The current through the $8\Omega$ resistor is (in Ampere) .

In a thermodynamic process, $50J$ of heat is going out of the system and $10J$ of work is done on the system. If the initial internal energy of the system was $60J$, then the final internal energy of the system will be

Two long parallel wires P and Q are both perpendicular to the plane of the paper with distance 5 m between them. If P and Q carry current of 2.5 amp and 5 amp respectively in the same direction, then the magnetic field at a point half way between the wires is

A person riding a car moving at 72 km/h sounds a whistle emitting a wave of frequency 1250 Hz. What frequency will be heard by another person standing on the road (i) in front of the car (ii) behind the car? Speed of sound in air = 340 m/s.

A block of mass $4\text{kg}$ is kept on an inclined plane having an angle of inclination ${37}^{\circ }$ attached with a spring of force constant $20\text{N/m}$ as shown in the figure. If the coefficient of friction between the block and incline is $0.8$, find the range in which the block can be at rest without slipping from its equilibrium position?

For a particle moving in a circle of radius $1\text{m}$, speed increases uniformly from $5\text{m/s}$ to $10\text{m/s}$ in $10\text{seconds}$. The value of angular acceleration of the particle is

A charged particle begins to move from the origin in a region which has a uniform magnetic field in the x-direction and a uniform electric field in the y- direction. Its speed is when it reaches the point (x, y, z) will depend

In the figure given below, with what acceleration does the block of mass $2m$ move? (Pulley and strings are massless and frictionless)

Current in the circuit will be

The instantaneous charges on capacitor in two discharging $RC$ circuits are plotted with respect to time as shown in figure below. Choose the correct statement(s) (where $E_1$ and $E_2$ are emfs of two DC sources in two different charging circuits and capacitors are fully charged initially).

A proton with kinetic energy of $1\text{MeV}$ moves from south to north. It gets an acceleration of ${10}^{12}{\text{ms}}^{-2}$ by an applied magnetic field (west to east). The value of magnetic field:

$\text{(Rest mass of proton is}1.6\times {10}^{-27}\text{kg})$

When two bodies collide elastically, then

A cart of mass M is at rest on a frictionless horizontal surface and a pendulum bob of mass m hangs from the roof of the art. The string breaks, the bob falls on the floor, makes several collisions on the floor and finally lands up in a small slot made in the floor. The horizontal distance between the string and the slot is L. Find the displacement of the cart during the process ?

A particle of charge $q$ and mass $m$ moving under the influence of uniform electric field $E\hat{i}$ and a uniform magnetic field $-B\hat{i}$ moves from point $\text{P}(0,a)$ to $\text{Q}(2a,a)$ where $\text{O}(0,0)$ is origin. The velocity of the particle at Point $\text{P}$ is $v\hat{i}$ and at $\text{Q}$ is $2v\hat{i}$. The rate of work done by the electric field & magnetic field on particle at point $\text{P}$ will be respectively:

If the resultant of two forces is of magnitude $P$ and equal to one of them and perpendicular to it, then the magnitude of other force is

1. 4

Consider a tank made of glass $\text{(refractive index 1.5)}$ with a thick bottom. It is filled with a liquid of refractive index $\mu$. A student finds that, irrespective of what the incident angle $i$ (see figure) is for a beam of light entering the liquid, the light reflected from the liquid glass interface is never completely polarized. For this to happen, the minimum value of $\mu$ is:

1. 5

As shown in the figure, the $2\text{kg}$ block is subjected to an external force of $42\text{N}$. What is the value of normal reaction ($N$) acting on the $3\text{kg}$ block (exerted on it by the surface), when spring reaches maximum extension? (Take $g=10{\text{m/s}}^2$)

In an interference of two similar waves with equal amplitudes $A_0$ and the intensity $I_0$. Determine the net intensity at a point where the path difference between two waves is $2\lambda$.