List of top Physics Questions

If the temperature of a liquid is raised, then its surface tension is _____

Equal masses of two substances of densities ρ ₁ and ρ₂ are mixed together. The density of the mixture would be

The end correction for the vibrations of air column in a tube of circular cross-section will be more if the tube is,

For aluminium the bulk modulus of elasticity is 7.5 x1010 N/m2 and density is 2.7 x103 kg/m2 . The velocity of longitudinal waves is aluminium is

Two forces of magnitude 5 N and 10 N act on a wooden block of mass 2 kg. If 5 N force acts towards right and 10 N force acts towards left, which one of following statements is correct?

The two factors on which the momentum of a body depends are ______ and _________ .

For ordinary terrestial experiments, the observer in an inertial frame in the following cases is

A Circular disc is rotating with angular velocity ω . A man standing at the edge walks towards the centre of the disc then the angular velocity ω.

The SI unit of gravitational constant is _____

___ system of units was accepted by the scientist of the general conference on weights and measures.

A car is standing $200\, m$ behind a bus, which is also at rest. The two start moving at the same instant but with different forward accelerations. The bus has acceleration $2 \, m/s^2$ and the car has acceleration $4 \, m/s^2$. The car will catch up with the bus after a time of :

A radioactive nucleus $A$ with a half-life $T$, decays into a nucleus $B$. At $t = 0$, there is no nucleus $B$. At sometime t, the ratio of the number of $B$ to that of $A$ is $0.3$. Then, $t$ is given by :

An observer is moving with half the speed of light towards a stationary microwave source emitting waves at frequency $10\, GHz$. What is the frequency of the microwave measured by the observer ? (speed of light $= 3 \times 10^8 \, ms^{-1}$)

In an experiment a convex lens of focal length $15\, cm$ is placed coaxially on an optical bench in front of a convex mirror at a distance of $5 \,cm$ from it. It is found that an object and its image coincide, if the object is placed at a distance of $20 \,cm $ from the lens. The focal length of the convex mirror is :

The temperature of an open room of volume $30 \, m^3$ increases from $17^{\circ}C$ to $27^{\circ}C$ due to the sunshine. The atmospheric pressure in the room remains $1 \times 10^5 \, Pa$. If $n_i$ and $n_f$ are the number of molecules in the room before and after heating, then $n_f-n_i$ will be :

The moment of inertia of a uniform cylinder of length $l$ and radius $R$ about its perpendicular bisector is $l$. What is the ratio $\frac{l}{R}$ such that the moment of inertia is minimum ?

A slender uniform rod of mass $M$ and length $l$ is pivoted at one end so that it can rotate in a vertical plane (see figure). There is negligible friction at the pivot. The free end is held vertically above the pivot and then released. The angular acceleration of the rod when it makes an angle $\theta$ with the vertical is :

In a physical balance working on the principle of moments, when $5\,mg$ weight is placed on the left pan, the beam becomes horizontal. Both the empty pans of the balance are of equal mass. Which of the following statements is correct ?

A time dependent force $F = 6t$ acts on a particle of mass $1\,kg$. If the particle starts from rest, the work done by the force during the first $1\,sec$. will be :

A body of mass $m=10^{-2} \, kg$ is moving in a medium and experiences a frictional force $F=-kv^2$. Its initial speed is $v_0=10 \, ms^{-1}$. If, after $10\,s$, its energy is $\frac{1}{8} mv_0{^{2}}$, the value of $k$ will be :

A conical pendulum of length $1\,m$ makes an angle $\theta = 45^{\circ}$ w.r.t. $Z-axis$ and moves in a circle in the $XY$ plane. The radius of the circle is $0.4 \,m$ and its center is vertically below $O$. The speed of the pendulum, in its circular path, will be : (Take $g = 10 \, ms^{-2}$)

In a coil of resistance $100 \, \Omega$, a current is induced by changing the magnetic flux through it as shown in the figure. The magnitude of change in flux through the coil is :

A capacitance of $2 \, \mu F$ is required in an electrical circuit across a potential difference of $1.0\, kV$. A large number of $1 \, \mu F$ capacitors are available which can withstand a potential difference of not more than $300\, V$. The minimum number of capacitors required to achieve this is :