Explore topic-wise InterviewSolutions in Current Affairs.

Five particles situated at the corners of a pentagon of side `a` move at a constant speed `v`. Each particle maintains a direction towards the particle at the next corner. Calculate the time the particles will take to meet each other ?

If the position vectors of three points $A,B,C$ are $\hat{i}+\hat{j}+\hat{k},2\hat{i}+3\hat{j}-4\hat{k}$ and $7\hat{i}+4\hat{j}+9\hat{k}$, then the unit vector perpendicular to the plane of the triangle $ABC$ is:

Neon gas of a given mass expands isothermally to double its original volume. What should be the fractional decrease in pressure, so that the gas when adiabatically compressed from that state, reaches the original state?

A moving-coil galvanometer has $100\text{turns}$ and each turn has an area $2.0{\text{cm}}^2$. The magnetic field produced by the magnet is $0.01\text{T}$. The deflection in the coil is $0.05\text{radian}$ when a current of $10\text{mA}$ is passed through it. Find the torsional constant of the suspension wire.

Equal masses of water and a liquid of density 2 are mixed together, then the mixture has a density of

Electric potential in a region is varying according to the relation $V=\frac{3x^2}{2}-\frac{y^2}{4}$ , where $x$ and $y$ are in $\text{meter}$ and $V$ is in $\text{volt}$. Electric field intensity in $\text{N/C}$ at a point $(1\text{m},2\text{m})$ is

A symmetric double convex lens is cut in two equal parts by a plane perpendicular to the principal axis. If the power of the original lens was 4D, the power of a cut-lens will be

Two charges $Q$ coulomb and $-Q$ coulomb are placed on a straight line as shown in the figure. Choose the correct graphical representation of potential $\left(V\right)$ versus distance $\left(r\right)$.

What is the maximum value of the force F such that the block shown in the arrangement, doesn't move?

A sound wave has a wavelength $\lambda$. The distance between the first compression and the fourth rarefaction is

Electrons of mass $m$ with de-Broglie wavelength $\lambda$ fall on the target in an X-rays tube. The cutoff wavelength $\left({\lambda }_0\right)$ of the emitted X-rays is

Light takes time $t_1$ to travel a distance $x_1$ in rarer medium($M_1$) and the same light takes time $t_2$ to travel a distance $x_2$ in a relatively denser medium($M_2$). The value of critical angle when light goes from medium $M_2$ to medium $M_1$ is :

Two metal rods of the same length and area of cross-section are fixed end to end between rigid supports. The materials of the rods have Young modulii $Y_1$ and $Y_2$, and coefficients of linear expansion ${\alpha }_1$ and ${\alpha }_2$. The junction between the rods does not shift if the rods are cooled.
(correct answer + 1, wrong answer - 0.25)

[CPMT 1990]

The upper half of an inclined plane of inclination $\theta$ is perfectly smooth, while the lower half is rough. A block, starting from rest at the top of the plane, again comes to rest at the bottom. The coefficient of friction between the block and lower half of the plane is -

A hydrogen atom in a state having a binding energy of 0.85 e V makes transition to a state with excitation energy 10.2 e V.

(a) Identify the quantum numbers n of the upper and the lower energy states involved in the transition.

(b) Find the wavelength of the emitted radiation.

A homogeneous solid cylindrical roller of radius $R$ and mass $M$ is pulled on a cricket pitch by a horizontal force. Assuming rolling without slipping, angular acceleration of the cylinder is:

A body of mass 2 kg is thrown upward with an energy 490 J. The height at which its kinetic energy would become half of its initial kinetic energy will be $[g=9.8m/s^2]$

Two particles A and B are moving with uniform velocities as shown in the figure given below at $t=0$. Find out the shortest distance between the two particles

A ball is thrown horizontally from a point 100 m above the ground with a speed of 20 m/s. Find

(a) The time it tskes to reach the ground,

(b) The horizontal distance it travels before reaching the ground,

(c) The velocity (direction and magnitude) with which it strikes the ground.

Work done in motion of the body over a closed loop for conservative forces is

An iceberg is floating partially immersed in sea water. The density of sea water is $1.03gc{m}^{-3}$ and that of ice is $0.92gc{m}^{-3}$. The approximate percentage of total volume of iceberg above the level of sea water is

Light of wavelength $5000\stackrel{\circ }{A}$ is falling on a photo sensitive surface. If the surface has received ${10}^{-7}$J of energy, then the number of photons falling on the surface will be

A plano convex lens fits exactly into a plano concave lens. Their plane surfaces are parallel to each other. If lenses are made of different materials of refractive index ${\mu }_1$ and ${\mu }_2$ and R is the radius of curvature of the curved surfaces of the lenses, then the focal length of the combination is:

A block of mass $m$ is in equilibrium on an inclined plane as shown.


Find out the normal force acting on the block

The following figure shows a logic gate circuit with two inputs $A$ and $B$ and the output $C$. The voltage waveforms of $A,B\text{and}C$ are shown below.





The logic circuit gate is :

A light ray is incident at ${30}^{\circ }$ on one of the two mirrors that are placed at right angle to each other. Find the angle of reflection for the ray reflected from mirror B.

A thin rectangular bar magnet suspended freely has a period of oscillation of $4\text{s}$. What will be the period of oscillation if the magnet is broken into two halves $($each having half the original length$)$ and one of the pieces is made to oscillate in the same field?

A current of $2\text{mA}$ was passed through an unknown resistor which dissipated a power of $4.4\text{W}$. Dissipated power when an ideal power supply of $11\text{V}$ is connected across it is

Equal charges each of 20 micro column are placed at x=0,2,4,8,16 cm on x-axis . find the force experienced by the charge at x=2 cm

A solid conducting sphere, having a charge $Q$, is surrounded by an uncharged conducting hollow spherical shell. Let the potential difference between the surface of the solid sphere and that of the outer surface of the hollow shell be $V$. If the shell is now given a charge of $-4Q$, the new potential difference between the same two surfaces is

In an isolated, charged, parallel plate air capacitor, the surface charge density on each plate has a magnitude $\sigma$. A dielectric slab with dielectric constant K is now introduced between the plates. The induced charge per unit area on the surface of the dielectric will be :

When a dolphin glides through air, it experiences an external pressure of $0.75\text{m}$ of mercury. The absolute pressure on dolphin when it is $4\text{m}$ below the free surface of the water is

$[\text{Take}g=10{\text{m/s}}^2]$

The value of $\underset{0}{\overset{\frac{\pi }{2}}{\int }}{\cos }^{5}x\cdot \cos 2xdx$ is equal to

A body cools down from ${80}^{\circ }\text{C}$ to ${60}^{\circ }\text{C}$ in 10 minutes when the temperature of surroundings is ${30}^{\circ }\text{C}$. The temperature of the body after next $10$ minutes will be

Two pendulums have time period $T$ and $5T/4$. They start $\text{SHM}$ at the same time from the mean position. What will be the phase difference between them at the moment, when bigger pendulum completes one oscillation?