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A solid disc and a ring, both of radius 10 cm are placed on a
horizontal table simultaneously, with initial angular speed equal to
10 π rad s^-1. Which of the two will start to roll
earlier? The co-efficient of kinetic friction is μ_k
= 0.2.

The total energy of an electron in the first excited state of hydrogen is about -3.4 eV. Its kinetic energy in this state is

1. 79.57

A charged body is kept in an electric field where it experiences a constant acceleration of 10 m/$s^2$ in the positive x-direction. The body hits wall after travelling 4 m and rebounds but can travel only upto 2 m before coming to rest momentarily . If the body was in contact with the wall for 12 ms then find the average acceleration of it due to the impact?

The potential energy of the system of two identically charged spherical shell as shown in the figure is equal to (Assume the charge distribution to be uniform on surface)

Two identical conducting rings P & Q of radius R are in pure rolling over a horizontal conducting plane with same speed (of center of mass) ‘v’ but in opposite direction . A constant magnetic field B is present pointing into the plane of paper. Then the potential between the highest points of two rings, is :

For a particle executing SHM, the displacement $x$ is given by $x=A\cos \omega t$. Choose the graph which represents the variation of potential energy as a function of time $t$ and displacement $x$.

For two non zero vectors $A$ and $B$, if $\overrightarrow{A}\times \overrightarrow{B}=\overrightarrow{B}\times \overrightarrow{A}$ then the angle between $\overrightarrow{A}$ and $\overrightarrow{B}$ is

Assuming that the mass M of the largest stone that can be moved by flowing river depends on the velocity of water V density of water p and the acceleration due to gravity G then M is directly proportional to

A transverse wave is described by the equation, $y=A\sin 2\pi (nt-\frac{x}{{\lambda }_0})$. The maximum particle velocity is equal to $3$ times the wave velocity, if

The activity of sample of radioactive materials is $A_1$ at time $t_1$ and $A_2$ at time $t_2(t_2>t_1)$. It's mean life is $T$, then

In the case of constants a and b of a transistor

Determine the electric dipole moment of the system of three charges, placed on the vertices of an equilateral triangle, as shown in the figure :

As shown in the figure, a circular sheet is removed from a uniform rectangular sheet. Find the horizontal distance of centre of mass of the remaining sheet from the origin $\text{O}$, after the removal of circular sheet. Use $\pi =\frac{22}{7}$ for calculation.

A car has to move on a level turn of radius 90 m. If the coefficient of static friction between the tyre and the road is 1.0, find the maximum speed the car can take without skidding.

The diagram shows a uniformly charged hemisphere of radius $R.$ It has volume charge density $\rho .$ If the electric field at a point $2R$ distance above its centre is $E$ then what is the electric field at the point which is $2R$ below its center?

body thrown up along a frictionless inclined plane of angle of inclination 30∘ covers a distance of 40 m along the plane. If the body id projected with the same speed at an angle of 30∘ with the ground, it will have a range of
(Take g=10 ms−2) please explain it clearly😣😥😥

A ring is made of a wire having a resistance $R_0=12\Omega$. Find the points $A$ and $B$ as shown in the figure, at which a current carrying conductor should be connected so that the resistance $R$ of the sub-circuit between these points is equal to $\frac{8}{3}\Omega$.

A string is stretched between fixed points separated by $75.0\text{cm}$. It is observed to have resonant frequencies of $420\text{Hz}$ and $315\text{Hz}$. There are no other resonant frequencies between these two. The lowest resonant frequency for this string is

A $9\text{kW}$ light source emits light of frequency ${10}^{15}\text{Hz}$. A parallel beam of this light falls normally on a surface. If the surface completely absorbs all the incident photons, the force exerted by the light beam on the surface is

Two travelling waves $y_1=Asin\left[k\right(x+ct\left)\right]$ and $y_2=Asin\left[k\right(x-ct\left)\right]$ are superposed on a string. The distance between adjacent nodes is

Balls of masses $4\text{kg}$ and $10\text{kg}$ are moving towards each other with speeds $6\text{m/s}$ and $3\text{m/s}$ respectively on a frictionless surface. After collision, the $4\text{kg}$ ball is observed to return back (towards left) with speed $2\text{m/s}$. Find the velocity of $10\text{kg}$ ball after collision.

Initially the capacitor is uncharged , find the charge on capacitor as a function of time, if switch is closed at $t=0$.

Three different dielectrics are filled in a parallel plate capacitor as shown. What should be the value of dielectric constant of a material , which when fully filled between the plates produces same capacitance ? (Asssume terminals are connected between $AC$ and $BD$).

Three aone dimensional mechanical waves in an elastic medium are given as $y1=2Asin(\omega t-kx),y2=2Asin(\omega -kx+\varphi )$

$y3=2Asin(\omega t+kx+\frac{\pi }{4})$ . For any value of $\varphi$ , the maximum displacement amplitude of the medium particles would be

In the figure, D is an ideal diode and an alternating voltage of peak value 10 volts is connected as input '$V_1$'.
Which of the following figures represents the correct waveform of output voltage $V_0$?

Three rods OA,OB,OC form a tripod meeting at O, and support a load P at O. If each rod be inclined at $\theta$ with the vertical and is of the same length L and their feet are at the apices of an equilateral triangle. The cross - sectional area of each member is A and the young's modulus is E.Vertical deflection of load P at O is ________.