Explore topic-wise InterviewSolutions in Current Affairs.

The pitch of a screw gauge is 0.5 mm and there are 50 divisions on the circular scale. In measuring the thickness of a metal plate, there are five divisions on the pitch scale (or main scale) and 34 division coincides with the reference line. Calculate the thickness of the metal plate.

Charges $q$ and $-q$ are placed at points $A$ and $B$ respectively which are a distance $4L$ apart. $C$ is the mid - point between $A$ and $B$. The work done in moving a charge $+Q$ along the semi-circle $CRD$ is

The vibrations of four air columns under identical conditions are represented in the figure below. The ratio of frequencies $f_p:f_q:f_r:f_s$ will be

In a series CR circuit shown in figure, the applied voltage is 10 V and the voltage across capacitor is found to be 8V. Then the voltage across R, and the phase difference between current and the applied voltage will respectively be

The motion of centre of mass of a system of two particles is unaffected by their internal forces

The mass and length of a wire are M and L respectively. The density of the material of the wire is d. On applying the force F on the wire, the increase in length is l, then the Young's modulus of the material of the wire will be

A box ${}^{\prime }{A}^{\prime }$ is lying on the horizaontal floor of the compartment of a train running along horizontal rails from left to right. At time ${}^{\prime }{t}^{\prime }$, it decelerates. then the reaction $R$ by the floor on the box is given best by

Small air bubble of radius $r$ is found to form at a depth of $H$ from the open surface of the liquid contained in a beaker. If $S$ is the surface tension, $\rho$ is the density of the liquid and $P_0$is the atmospheric pressure, then the pressure inside the bubble is

A sound wave of frequency n travels horizontally to the right with speed c. It is reflected from a broad wall moving to the left with speed v. The number of beats heard by a stationary observer to the left of the wall is

The input signal given to a a CE amplifier having a voltage gain of $150$ is $V_i=2\cos (15t+\frac{\pi }{3})$. The corresponding output signal will be

A hockey player applies an average force of $60\text{N}$ to $250\text{g}$ hockey puck for a time of $100\text{ms}$. The impulse experienced by the hockey puck is

Find the force $F$ acting on the body of mass $6\text{kg}$ to move it with an acceleration of $1.5{\text{m/s}}^2$. Take $g=10{\text{m/s}}^2$.

Physical independence of force is a consequence of which law/laws of motion?

In the given constraint, if the string is inextensible and pulley is frictionless, then magnitude of velocity of block $A$ $\left(V_A\right)$ is

In Young's double slit experiment, if one of the slit is closed fully, what will be visible on the screen?

A uniform cube is subjected to volume compression. If each side is decreased by 1%, then bulk strain is</br>

On heating a liquid of coefficient of cubical expansion g in a container having coefficient of linear expansion $\frac{g}{3}$, the level of liquid in the container will

A constant retarding force of 50 N is applied to a body of mass 20 kg moving initially with a speed of $15m{s}^{-1}$ . How long does the body take to stop?

In stationary wave

[MP PET 1987; BHU 1995]

A parallel-plate capacitor has plate are 20 cm^{2, plate separation 1.0 mm and a dielectric slab of dielectric constant 5.0 filling up the space between the plates. This capacitor is joined to a battery of emf 6.0 V through a 100 k $\Omega$ resistor. Find the energy of the capacitor 8.9 $\mu s$after the connections are made.

Two identical photo-cathodes receive light of frequencies $f_{1}and{f}_2$. If the velocities of the photo electrons (of mass m) coming out are respectively $v_{1}and{v}_2$, then

For the stationary wave y = 4 sin $\left(\frac{\pi x}{15}\right)cos\left(96\pi t\right)$ , the distance between

anodeand the next antinode is

[MP PMT 1987]

Which of the following would have a permanent dipole moment

In the figure shown the cart of mass '6m' is initially at rest. A particle of mass 'm' is attached to the end of the light rod which can rotate freely about A. If the rod is released from rest in a horizontal position shown, determine the velocity $v_{rel}$of the particle with respect to the cart when the rod is vertical.

A steel rod of cross-sectional area $4c{m}^2$ and length 2 m shrinks by 0.1 cm as the temperature decreases in night. If the rod is clamped at both ends during the day hours, find the tension developed in it during night hours. Young modulus of steel = $1.9\times {10}^{11}N{m}^{-2}$.

A man is $25\text{m}$ behind a bus, when the bus starts accelerating at $2{\text{m/s}}^2$ and man starts moving with constant velocity of $10\text{m/s}$. Time taken by him to board the bus is

A car starts from rest on a half kilometer long bridge. The coefficient of friction between the tyre and the road is 1.0. Shwo that one cannot drive through the bridge in less tahn 10 s.

Choose the correct answer
The area bounded the curve y = x|x| X- axis and the coordinates x =- 1 and x = 1 is given by
(a) $0$ (b) $\frac{1}{3}$
(c) $\frac{2}{3}$ (d) $\frac{4}{3}$

The logic behind 'NOR' gate is that it gives

A cubical block (side $2\text{m}$) of mass $20\text{kg}$ slides on inclined plane lubricated with the oil of viscosity $\eta ={10}^{-1}\text{Poise}$ with constant velocity of $10\text{m/s}$. Find out the thickness of the layer of liquid. $(g=10{\text{m/s}}^2)$

A cubical block of side $a$ is moving with velocity $v$ on a horizontal smooth plane as shown. It hits a ridge at point $O$. The angular speed of the block after it hits $O$ is

Two identical air capacitors A and B of the parallel plate type are charged to the same potential and connected in parallel (+ to +). Now a dielectric is inserted between the plates of A, then

The above picture depicts the possible transitions of electron in Bohr's atomic model.
Match the transition lines to corresponding series.
$\begin{array}{cc}\text{p.}{L}_1& \text{i. Lyman}\\ \text{q.}{L}_2& \text{ii. Blamer}\\ \text{r.}{L}_3& \text{iii. Paschen}\\ \text{s.}{L}_4& \text{iv. None of these}\end{array}$

The sphere shown in figure lies on a rough plane when a particle of mass m travelling at a speed v0 collides and sticks with it. If the line of motion of the particle is at a distance h above the plane, find the linear speed of the combined system just after the collision. Assume that the mass M of the sphere is large compared to the mass of the particle so that the centre of mass of the combined system is not appreciably shifted from the centre of the sphere.

The destiny of parallel rays in a spherical mirror (within paraxial approximation) is :

The period of oscillation of a simple pendulum of length L suspended from the roof of a vehicle which moves without friction down in an inclined plane of inclination $\alpha ,$ is given by

When photons of energy 4.25 eV strike the surface of a metal A, the ejected photoelectrons have maximum kinetic energy $(KE{)}_A$ and de-Broglie wavelength is ${\lambda }_A$. The maximum kinetic energy of photoelectrons liberated from another metal B by photons of energy 4.7 eV is $(KE{)}_B$, where $(KE{)}_B=(KE{)}_A–1.5$ eV. If the de-Broglie wavelength of these photoelectrons is ${\lambda }_B(=2{\lambda }_A)$, then:

Categorize the following motion as being either an example of +ve or –ve acceleration.

i. Moving in the +ve direction and speeding up = _____________

ii. Moving in the +ve direction and slowing down = ______________

iii. Moving in the -ve direction and speeding up = ______________

iv. Moving in the -ve direction and slowing down = _______________

The acceleration of a particle starting from rest varies with time according to the relation $a=kt+c$. The velocity $v$ of the particle after time $t$ will be

A rod OA of mass m and length L is rotating in a horizontal circle about point O as shown in figure. B is the mid-point of rod. If T represents tension in the rod at any point and U represents elastic potential energy per unit volume at any point of rod, then choose correct alternative (s).

The momentum of an electron in an orbit is $\frac{h}{\lambda }$ where $h$ is plank's constant and $\lambda$ is wavelength associated with it. The nuclear magneton of electron of charge $e$ and mass $m_e$ is given as ${\mu }_n=\frac{eh}{3672\pi m_e}$. The dimensions of ${\mu }_n$ is

Two wires A and B of same length, same area of cross-section having the same Young's modulus are heated to the same range of temperature. If the coefficient of linear expansion of A is 3/2 times of that of wire B. The ratio of the forces produced in two wires will be

A closed organ pipe of length L and an open organ pipe contain gases of densities ${\rho }_1$ and ${\rho }_2$ respectively. The compressibility of gases are equal in both the pipes. Both the pipes are vibrating in their second overtone with same frequency. The length of the open organ pipe is

A cylindrical tube, open at both ends, has a fundamental frequency $f_0$, in air. The tube is dipped vertically into water such that half of its length is inside water. The fundamental frequency of the air column now is