List of top Physics Questions

The viscous force acting on a rain drop of radius 0.35 mm falling through air with a velocity of 1 m/s, is $ \text{1 km}/{{\text{s}}^{\text{2}}} $

Two narrow capillary tubes A and B are of lengths ( and 111 and of same radius r. The rate of flow of water through the tube A under a constant pressure head P is 3 $ \sqrt{\text{49}0}\text{ m}/\text{s} $ . If A and B are connected in series and the same pressure difference P is maintained between the ends of the composite tube, then the rate of flow of water is :

The displacement time graph for two bodies A and B are straight lines inclined at 30? and 60? respectively with the time axes. If $ \upsilon =\sqrt{4rg} $ and $ \upsilon =\sqrt{4\times 2.5\times 9.8} $ are their velocities, then $ \upsilon =\sqrt{98}\,\,m/s $ will be :

The maximum and minimum tensions in the string whirling in a circle of radius 2.5 m are in the ratio 5:3 then its velocity is :

A cannon of mass 1000 kg, located at the base of an inclined plane fires a shell of mass 100 kg in a horizontal direction with a velocity 180 km/h. The angle of inclination of the inclined plane with the horizontal is $ 45{}^\circ $ . The coefficient of friction between the cannon and the inclined plane is 0.5. The height, in m, to which the cannon ascends the inclined plane as a result of the recoil is: $ (g=10m/{{s}^{2}}) $

Four particles, each of mass 1 kg, are placed at the corners of a square of side 1m in the X- Y plane. If the point of intersection of the diagonals of the square, is taken as the origin, the co-ordinates of the centre of mass are:

The maximum height reached by a projectile is 4 m. The horizontal range is 12 m. Velocity of projection in ms-1, is : ( g = acceleration due to gravity)

A thin converging lens is made up of glass of refractive index 1.5. It acts like a concave lens of focal length 50 cm, when immersed in a liquid of refractive index $ \left( \frac{15}{8} \right) $ . The focal length of the converging lens in air is, in metre:

A ball of mass $2 \,kg$ and another of mass $4\, kg$ are dropped together from a $60$ feet tall building. After a fall of $30$ feet each towards earth, their respective kinetic energies will be in the ratio of

A block of mass $m$ is placed on a smooth wedge of inclination $\theta$. The whole system is accelerated horizontally so that the block does not slip on the wedge. The force exerted by the wedge on the block will be ($g$ is acceleration due to gravity)

The energy stored in a condenser is in the form of

Source of sound and the observer are mutually at rest. If the speed of sound is changed, then the frequency of sound heard by the observer will appear to be

Two springs of spring constants $ k_1 $ and $ k_2$ are joined in series. The effective spring constant of the combination is given by

A galvanometer of $50$ ohm resistance has $25$ divisions. $A$ current of $ 4\times 10^{-4}$ ampere gives a deflection of one division. To convert this galvanometer into a voltmeter having a range of $25$ volts, it should be connected with a resistance of

Blowing air with open mouth is an example of ...........

A body of mass $m$ rests on horizontal surface, the coefficient of friction between the body and the surface is $\mu$. if the mass is pulled by a force $P$ as shown in the figure, the limiting friction between body and surface will be:

A bar magnet is equivalent to ............

Oxygen is $16$ times heavier than hydrogen. Equal volumes of hydrogen and oxygen are mixed. The ratio of speed of sound in the mixture to that in hydrogen is _____

Sound waves in air are always longitudinal because,

A bullet moving with a speed of $100\, ms ^{-1}$ can just penetrate two planks of equal thickness. Then, the number of such planks penetrated by the same bullet when the speed is doubled will be ...........

Effective capacitance between A and B in the figure shown is (all capacitances are in $\mu\, F$ )

A spherical drop of capacitance $1 \mu \,F$ is broken into eight drops of equal radius. Then, the capacitance of each small drop is ........

An unknown resistance $R_{1}$ is connected in series with a resistance of $10 \Omega .$ This combination is connected to one gap of a metre bridge while a resistance $R_{2}$ is connected in the other gap. The balance point is at $50\, cm$. Now, when the $10 \Omega$ resistance is removed the balance point shifts to $40 cm$. The value of $R_{1}$ is (in ohm)

A thin plano-convex lens acts like a concave mirror of focal length $0.2\, m$ when silvered from its plane surface. The refractive index of the material of the lens is $1.5.$ The radius of curvature of the convex surface of the lens will be ............

Three long straight wires $A, B$ and $C$ are carrying currents as shown in figure. Then the resultant force on $B$ is directed .............