Explore topic-wise InterviewSolutions in Current Affairs.

Given $\overrightarrow{C}=\overrightarrow{A}\times \overrightarrow{B}$ and $\overrightarrow{D}=\overrightarrow{B}\times \overrightarrow{A}$, Then the angle between $\overrightarrow{C}$and $\overrightarrow{D}$ is.

A glass sinker has a mass $M$ in the air. When weighed in a liquid at temperature $t_1$, the apparent mass is $M_1$ and when weighed in the same liquid at temperature $t_2$, the apparent mass is $M_2$. If the coefficient of cubical expansion of the glass is ${\gamma }_g$, then coefficient of expansion of the liquid is

From a tower of height $H$, a particle is thrown vertically upwards with a speed $u$. The time taken by the particle to hit the ground, is $n$ times that taken by it to reach the highest point of its path. The relation between $H$,$u$ and $n$ is

If the binding energy of electrons in a metal is $250{\text{kJmol}}^{-1}$ then, the threshold frequency of the metal is:

A solid sphere of mass $m$ and radius $R$, is rolling without slipping, along a horizontal surface. Find the total angular momentum of the sphere, about the point of contact. The speed of its centre of mass is $v_0$

A ball of mass $m$ moving with a velocity of $3{\text{ms}}^{-1}$ along $x$-axis strikes another ball of mass $2m$ kept at rest. The first ball comes to rest after collision and the other one breaks into two equal pieces, one of the pieces starts moving along $+y$-axis with speed $4{\text{ms}}^{-1}$, what will be the velocity of the other piece ?

A plane electromagnetic wave propagating in the $x-$direction in vacuum has wavelength of $6.0\text{mm}$. The electric field is in the $y-$direction and its maximum magnitude is $33{\text{Vm}}^{-1}$.



$\left(i\right)$ The equation for the electric field as a function of $x\left(\text{m}\right)$ and $t\left(\text{s}\right)$ is.



​​​​​​​$[$1 Mark$]$

If a charged particle $(q,m)$ enters into the transverse magnetic field at origin with velocity $v_0\hat{i}$, then find the maximum possible positive $x-$coordinate of the particle, if the magnetic field is given as;

$B=B_{0}x(-\hat{k}),x\ge 0$

$B=0,x<0$

A vessel of volume $2000c{m}^3$ contains 0.1 mole of $O_2$ and 0.2 mole of $C{O}_2$. If the temperature of the mixture is 300k, find its pressure.

If $y=2{\sin }^2\theta +\tan \theta$, then $\frac{dy}{d\theta }$ will be

A perfectly elastic ball $P_1$ of mass m moving with velocity v collides elastically with three exactly similar balls $P_2,P_3,P_4$ lying on a smooth table as shown. Velocities of the four balls after the collision are

The area(in $\text{sq.units}$) enclosed between the curve $y=x^2$ and $y=\frac{2}{1+x^2}$ is

A cubical block of side $0.5\text{m}$ floats on water with $30\%$ of its volume under water. What is the maximum weight that can be put on the block without fully submerging it under water? [Take, density of water $={10}^3{\text{kg/m}}^3]$

A plane mirror is inclined at an angle of ${45}^{\circ }$ with the horizontal and having one of its end at the origin(O) as shown in figure. An object is kept at $x=-2\text{cm}$. The position coordinates of the image of $P$ will be

A particle of mass m is moving in a circular path of constant radius r such that its centripetal acceleration ac is varying with time t as ac=k2rt2 where k is a constant. The power delivered to the particle by the force acting on it is-

X-rays are produced by jumping of

Sir/madam,

In Byju's lessons of mechanical properties of fluids, fluid flow and bernouli's principle are being taught first but in NCERT those topics came after surface tension and surface energy.

so plz suggest me in which way should i follow it

in the NCERT way or in the way it's being given.

1. 0.5

In the Column I below, four different paths of a particle are given as functions of time.

In these functions, $\alpha$ and $\beta$ are positive constants of appropriate dimensions and $\alpha \ne \beta .$ In each case, the force acting on the particle is either zero or conservative.

In Column II, five physical quantities of the particle are mentioned: $\overrightarrow{p}$ is the linear momentum $\overrightarrow{L}$ is the angular momentum about the origin, $K$ is the kinetic energy, $U$ is the potential energy and $E$ is the total energy.

Match each path in Column I with those quantitites in Column II, which are conserved for that path.

$\begin{array}{cc}\text{Column~I}& \text{Column~II}\\ \left(A\right)\overrightarrow{r}\left(t\right)=\alpha t\hat{i}+\beta t\hat{j}& 1.\overrightarrow{p}\\ \left(B\right)\overrightarrow{r}\left(t\right)=\alpha \cos \omega t\hat{i}+\beta \sin \omega t\hat{j}& 2.\overrightarrow{L}\\ \left(C\right)\overrightarrow{r}\left(t\right)=\alpha (\cos \omega \hat{i}+\sin \omega t\hat{j})& 3.K\\ \left(D\right)\overrightarrow{r}\left(t\right)=\alpha t\hat{i}+\frac{\beta }{2}{t}^2\hat{j}& 4.U\\ & 5.E\end{array}$

In Young's double slit arrangement, slits are separated by a gap of $0.5\text{mm}$, and the screen is placed at a distance of $0.5\text{m}$ from them. The distance between the first and the third bright fringe formed when the slits are illuminated by a monochromatic light of $5890\text{Å}$ is:

If the body is moving in a circle of radius r with a constant speed v, its angular velocity is

Evaluate

$\sin ({180}^{\circ }-x).\cot ({270}^{\circ }+x).\tan ({270}^{\circ }-x).\sec ({180}^{\circ }+x)$

A spherical mirror having focal length $f=-25\text{cm}$ is used to obtain an image which is of the same size as that of the object. What should be the object distance $\left(u\right)$ as per sign convention?

A physical quantity is measured and the result is
expressed as nu where u is the unit used and n is the
numerical value. If the result is expressed in various
units then .

A steel scale measures the length of a copper wire as $80.0\text{cm}$ when both are at ${20}^{\circ }\text{C}$ (the calibration temperature for the scale). What would be the scale reading for the length of the wire when both are at ${40}^{\circ }\text{C}$? (Given ${\alpha }_{\text{steel}}=11\times {10}^{-6}/{}^{\circ }\text{C}$ and ${\alpha }_{\text{copper}}=17\times {10}^{-6}/{}^{\circ }\text{C})$

1. 0.04

A ray of light falls on one face of an equilateral glass prism at ${45}^{\circ }$ and emerges from the other face at the same angle. The deviation suffered by the ray is

If a load of 9 kg is suspended on a wire, the increase in length is \(4.5 mm\). The force constant of the wire is

1. 10.6