Explore topic-wise InterviewSolutions in Current Affairs.

Acceleration due to gravity near the surface of the earth is and independent of a body.

According to a stationary observer on ground, a point object $O$ in front of a plane mirror $M$ and the mirror both are moving at $10\text{cm/s}$ and $20\text{cm/s}$ respectively towards right. Find the speed of the image as measured by the stationary observer.

A solid sphere of mass $m$ is released from rest from the rim of a hemspherical cup so that it slides along the surface. If the rim of the hemisphere is kept horizontal, find the normal force exerted by the cup on the ball when the ball reaches the bottom of the cup. Neglect the radius of the ball as compared to the radius of the cup.

An X-ray tube operates at 20 kV. A particular electron loses 5% of its kinetic energy to emit an X-ray photon at the first collision. What is the wavelength corresponding to this photon? Given that Planck's constant $=4.14\times {10}^{-15}eVs$.

In a gravity free space, a spacecraft of mass $10\text{kg}$, having $20\text{kg}$ of fuel is initially at rest. The fuel is ignited and the exhaust velocity is $0.1\text{km/s}$. Then, speed gained by the spacecraft when the fuel is fully consumed is

Light of wavelength 5000 $\stackrel{\circ }{A}$ falls on a sensitive plate with photoelectric work function of 1.9 eV. The kinetic energy of the photoelectron emitted will be

The force between two alpha particles separated by a distance r is f.in order to have same force f the distance between singly ionized chlorine atoms separated by a distance of

1. 2r

2.4r

3.r/2

4.r/4

A force $F=-\frac{k}{x^2}(x\ne 0)$ acts on a particle in $x-$direction. Find the work done by this force in displacing the particle from $x=+a$ to $x=+2a.$ Here $k$ is a positive constant.

A particle P moving with speed 'v' undergoes a head-on elastic collision with another particle Q of identical mass and at rest. After the collision,

The Diesel Generator you saw usually in Family functions or industries converts ___.

Beats are the result of

[CPMT 1971; J & K CET 2002]

A force of 100N is applied on a body of mass 2kg at rest for 3 seconds. What will be velocity of the body after 10 seconds of application of the force assuming no friction?

The magnetic field in the cylindrical region shown in figure increases at a constant rate of 20.0 mT/s. Each side of the wquare loop abcd and defa has a length of 1.00 cm and a resistance of 4.00 $\Omega$. Find the current (magnitude and sense) in the wire ad if

(a) The switch $S_1$ is closed but $S_2$ is open

(b) $S_1$ is open but $S_2$ is closed

(c) Both $S_1$ and $S_2$ are open and

(d) Both $S_1$ and $S_2$ are closed

The combination of two bar magnets makes 10 oscillations per second in an oscillation magnetometer when like poles are tied together and 2 oscillation per second when unlike poles are tied together. Find the ratio of the magnetic moments of the magnets. Neglect any induced magnetism.

The length and the radius of a cylinder measured with a slide callipers are found to be 4.54 cm and 1.75 em respectively. Calculate the volume of the cylinder.

A road is banked at an angle of $\theta ={30}^{\circ }$ and provides a coefficient of static friction ${\mu }_s=0.4$. The road gets seriously damaged if it experiences a normal reaction force of more than $10000\text{N}$. What should be the maximum mass of the vehicle allowed on this road?

A metallic rod of mass 20 kg and of uniform thickness rests against a wall while the lower end of the rod is in contact with floor. The rod makes an angle of ${60}^o$ with floor. If the weight of rod produces a torque 150 Nm about its lower end, the length of the rod is (g = 10$m{s}^{-2}$)

Plane polarised light is passed through a polaroid. On viewing through the polaroid we find that when the polaroid is given one complete rotation about the direction of the light, one of the following is observed

[MNR 1993]

Which of the following equipment is used for electrolysis of water?

Two particle A and B are in motion. If the wavelength associated with 'A' is 33.33 nm, the wavelength associated with 'B' whose momentum is $\frac{1}{3}rd$ of 'A' is

In a PN-junction diode [MP PET 1993]

The graph, shown in the adjacent figure, shows the fall of temperature (T) of two bodies x and y, having the same surface area, with time (t) due to emission of radiation. Find the correct relation between emissivity power (E) and absorptive power (a) of the two bodies

A mercury arc lamp provides $0.1\text{W}$ of ultra-violet radiation at a wavelength of $\lambda =2537\stackrel{\circ }{A}$ only. The photo tube (cathode of photo electric device) consists of potassium and has an effective area of $4c{m}^2$. The cathode is located at a distance of $1\text{m}$ from the radiation source. The work function for potassium is ${\varphi }_0=2.2eV$.

To what saturation current does the flux of photons at the cathode corresponds, if the photo conversion efficiency is $5\%$?

A certain dye absorbs light of $\lambda =4530A^0$ and then fluoroscence light of $5080A^0$.Assuming that under given conditions 47% of the absorbed energy is reemited out as fluoroscence the ratio of quanta emitted out to the number of quanta absorbed.

Starting form rest a particle is first accelerated for time $t_1$ with constant acceleration $a_1$ and then stops in time $t_2$ with constant retardation $a_2$. Let $v_1$ be the average velocity in this case and $s_1$ be the total displacement. In the second case, it is accelerated for the same time $t_1$ with constant acceleration $2a_1$ and comes to rest with constant retardation $a_2$ in time $t_3$. If $v_2$ is the average velocity in this case and $s_2$ the total displacement. Then

The pictograph is the representation of data in ___

In an LCR circuit, at resonance

Inside a smooth spherical cavity, particles A can slide freely. The block having this cavity is moving horizontally with constant acceleration $a_0=10m/s^2$.

The particle is released from rest (w.r.t. block) from its initial position as shown in the figure. The angle $\theta$ with the horizontal, when the particle will have maximum speed with respect to the block is

A streamlined body falls through air from a height h on the surface of a liquid. If d and D(D > d) represents the densities of the material of the body and liquid respectively, then the time after which the body will be instantaneously at rest, is

Four charge particles $H{e}^{++}$, proton, deutron and $L{i}^{++}$ enters a region of uniform magnetic field and moves in a circular path of different radius. List I gives above four particles while list II gives magnitude of some quantity.

$\begin{array}{cc}\text{List I}& \text{List II}\\ \text{I -}H{e}^{++}& \text{P)}1\\ \text{II -}\text{Proton}& \text{Q)}2\\ \text{III -}\text{deutron}& \text{R)}\frac{1}{\sqrt{2}}\\ \text{IV)}L{i}^{++}& \text{S)}\sqrt{2}\\ & \text{T)}\frac{\sqrt{7}}{2}\\ & \text{U)}\frac{1}{2}\end{array}$
If kinetic energy of all four particles is same than correct match for radius of four particles in units of radius of proton is

A body of mass $M$ is dropped from a height $h$ on a sand floor. If the body penetrates $x\text{m}$ into the sand, the average resistance offered by the sand to the body is

A car is negotiating a curve of radius R = 20 m on a banked road with banking angle $\theta$ and coefficient of friction $\mu$. Take speed of car as v.

$\begin{array}{cccccc}& \text{Column 1}& & \text{Column 2}& & \text{Column 3}\\ \left(I\right)& v=10\sqrt{2}m/s& \left(i\right)& \mu =0.2& \left(p\right)& \theta ={30}^{\circ }\\ \left(II\right)& v=20m/s& \left(ii\right)& \mu =0.4& \left(Q\right)& \theta ={45}^{\circ }\\ \left(III\right)& v=50m/s& \left(iii\right)& \mu =0.6& \left(R\right)& \theta ={37}^{\circ }\\ \left(IV\right)& v=5m/s& \left(iv\right)& \mu =0.8& \left(S\right)& \theta ={60}^{\circ }\end{array}$

In which case will the friction be zero ?

Given a ring of mass $M$, radius $r$ resting on a rough horizontal plane having coefficient of friction $\mu$. A cylindrical vertical magnetic field passing through ring is switched on at $t=0$ which varies with time as $B=K{t}^2$. If the ring has charge $Q$ distributed uniformly over it. Find the time after which ring starts rotating.

In a cylindrical structure, magnetic field $B$ is changing as $B=B_0+\alpha t$. The value of emf induced in the loop shown in the figure is (Given Line $AOB$ is circular and $\alpha ,B_0$ are constant values).

An equi convex lens is made of a material of refractive index ${\mu }_1$ and is placed inside two liquids of refractive indices ${\mu }_2$ and ${\mu }_3$ as shown with ${\mu }_2>{\mu }_1>{\mu }_3$. A wide, parallel beam of light is incident on the lens from the left. The lens will give rise to:

Three particles $A,B$ and $C$ of masses $m,2m$ and $4m$ are placed on a straight line of length $2L$ as shown. Find the moment of inertia about an axis passing through $B$ and perpendicular to the line $AC$

A body cools in $7$ min from ${60}^{\circ }\text{C}$ to ${40}^{\circ }\text{C}$. What will be its temperature after the next $7$ min ?
The temperature of surroundings is ${10}^{\circ }\text{C}$. [Assume Newton's Law of cooling is applicable]

uniform circular disc of mass 200 g and radius 4.0 cm is rotated about one of its diameter at an angular speed of 10 rad/s. Find the angular momentum about the axis of rotation

The potential energy of a certain spring when stretched through a distance 'S' is 10 joule. The amount of work (in joule) that must be done on this spring to stretch it through an additional distance 'S' will be

If $\overrightarrow{a}\text{and}\overrightarrow{b}$ are two vectors perpendicular to each other and $|\overrightarrow{a}|=\overrightarrow{b}|=1$, determine the angle between $(\overrightarrow{a}+\overrightarrow{b})\text{and}(2\overrightarrow{a}+\overrightarrow{b})$

A sound wave of wavelength $50\text{cm}$ travels in a gas medium. If the difference between the maximum and minimum pressures at a given point is $5\times {10}^{-3}{\text{N/m}}^2$ and the amplitude of vibration of the particles of the medium is $5\times {10}^{-10}\text{m}$, find bulk modulus of the medium.