List of top Physics Questions

A boy of mass $m$ stands on one end of a wooden planck of length $L$ and mass $M$. The plank is floating on water. If the boy walks from one end of the plank to the other end at a constant speed, the resulting displacement of the plank is given by

Water is flowing in streamline motion through a horizontal tube. The pressure at a point in the tube is $p$ where the velocity of flow is $v$. At another point, where the pressure is $p/2$, the velocity of flow is [density of water = $?$]

Two non-conducting solid spheres of radii $R$ and $2R$ , having uniform volume charge densities $\rho _1 $ and $ \rho _2 $ respectively, touch each other. The net electric field at a distance $2R$ from the centre of the smaller sphere, along the line joining the centre of the spheres, is zero. The ratio $\rho _1 \, / \, \rho _2 $ can be

The work done on a particle of mass $m$ by a force $K \left[\frac{ x }{\left( x ^{2}+ y ^{2}\right)^{3 / 2}} \hat{ i }+\frac{ y }{\left( x ^{2}+ y ^{2}\right)^{3 / 2}} \hat{ j }\right]$ ( $K$ being a constant of appropriate dimensions, when the particle is taken from the point $( a , 0)$ to the point $(0, a )$ along a circular path of radius a about the origin in the $x$-y plane is

The ratio of the radii of the nuclei $ _{13}Al^{27} $ and $ _{52}Te^{125} $ is

The initial rate of hydrolysis of methyl acetate $(1 M)$ by a weak acid $(HA, 1M) $ is 1/100th of that of a strong acid $(HX, 1M)$, at $ 25^{\circ} C.$ The $ K_a ( H A ) $ is

The electric field in a region is given by $ E=\frac{A}{x^{3}}\,\hat{i}+By\,\hat{j}+Cz^{2}\,\hat{k} $ The $ SI $ units of $ A $ , $ B $ and $ C $ are, respectively

In a new system of units called star units, $ 1\,kg^* = 10 \,kg $ , $ 1 \,m^* =1 \,km $ and $ 1s^* = 1 $ minute, what will be the value of $ 1J $ in the new system ?

Figure shows a series $LCR$ circuit with $R = 200 \,\Omega,\, C = 15.0\, \mu F$ and $L = 230\, mH$. If $\varepsilon = 36.0\, sin\, 120\pi t$, the amplitude $I_{0}$ of the current $I$ in the circuit is close to

Figure gives the acceleration of a $2.0 \,kg$ body as it moves from rest along $x$ axis while a variable force acts on it from $ x=0\,m $ to $ x=9\,m $ . The work done by the force on the body when it reaches (i) $ x=4\,m $ and (ii) $ x=7\,m $ shall be as given below

An object and its real image are located at distances $25\, cm$ and $40 \,cm$ respectively from the two principal foci of a convex lens. The linear magnification of the image is near to

A uniform rope of mass $ 0.1 \,kg $ and length $ 2.45 \,m $ hangs from a ceiling. The time taken by a transverse wave to travel the full length of the rope is

A thermodynamic state of a given sample of an ideal gas is completely described, if its

A steady current $I$ flows along an infinitely long hollow cylindrical conductor of radius $R$. This cylinder is placed coaxially inside an infinite solenoid of radius $2R$. The solenoid has $n$ turns per unit length and carries a steady current $I$. Consider a point $P$ at a distance $r$ from the common axis. The correct statement(s) is (are)

A particle of mass $m$ is projected from the ground with an initial speed $u _{0}$ at an angle $\alpha$ with the horizontal. At the highest point of its trajectory, it makes a completely inelastic collision with another identical particle, which was thrown vertically upward from the ground with the same initial speed $u_{0}$. The angle that the composite system makes with the horizontal immediately after the collision is

A particle of mass $M$ and positive charge $Q$, moving with a constant velocity $u _{1}=4 \hat{i}ms ^{-1}$, enters a region of uniform static magnetic field normal to the $x$-y plane. The region of the magnetic field extends from $x =$ 0 to $x = L$ for all values of $y$. After passing through this region, the particle emerges on the other side after 10 milliseconds with a velocity $\vec{ u }_{2}=2(\sqrt{3} i +\hat{ j }) m / s ^{-1}$. The correct statement(s) is (are)

A microscope is focused on a coin lying at the bottom of a beaker. The microscope is now raised up by $1 cm$. To what depth should the water be poured into the beaker so that coin is again in focus? (Refractive index of water is $\frac{4}{3}$ )

A magnifying glass of focal length $ 5\,cm $ is used to view an object by a person whose smallest distance of distinct vision is $ 25\,cm $ . If he holds the glass close to eye, the magnification is

A glass plate of refractive index $1.5$ is coated with a thin layer of thickness t and refractive index $1.8$. Light of wavelength $648 \,nm$ travelling in air is incident normally on the layer. It is partly reflected at upper and lower surfaces of the layer and the two reflected rays interfere. The least value of $t$ for which the rays interfere constructively is

A cyclotron is operated at an oscillator frequency of $ 12\, MHz $ and has a dee radius $ R = 50\,cm $ . What is the magnitude of the magnetic field needed for a proton to be accelerated in the cyclotron ?

The image of an object, formed by a plano-convex lens at a distance of $8\,m$ behind the lens, is real and is one-third the size of the object. The wavelength of light inside the lens is $\frac{2}{3}$ times the wavelength in free space. The radius of the curved surface of the lens is

Two non-reactive monoatomic ideal gases have their atomic masses in the ratio $2 : 3$. The ratio of their partial pressures, when enclosed in a vessel kept at a constant temperature, is $4 : 3$. The ratio of their densities is

A ray of light travelling in the direction $\frac{1}{2}(\hat{i}+\sqrt{3})$ is incident on a plane mirror. After reflection, it travels along the direction $\frac{1}{2}(\hat{i}-\sqrt{3} j)$. The angle of incidence is

In the Young's double slit experiment using a monochromatic light of wavelength $\lambda$ the path difference (in terms of an integer $n$) corresponding to any point having half the peak intensity is

Using the expression 2d sin $\theta =\lambda,$ one calculates the values of d by measuring the corresponding angles $\theta$ in the range 0 to 90$^{\circ}$. The wavelength X is exactly known and the error in $\theta$ is constant for all values of $\theta$. As $\theta$ increases from 0$^{\circ}$