List of top Physics Questions

Two spherical soap bubbles of radii '$a$' and '$b$' in vacuum coalesce under isothermal conditions. The resulting bubble has a radius equal to}

A block of mass '$M$' rests on a piston executing S.H.M. of period one second. The amplitude of oscillations, so that the mass is separated from the piston, is (acceleration due to gravity, $g = 10 \text{ ms}^{-2}, \pi^2 = 10$ )}

A solid cylinder and a solid sphere having same mass and same radius roll down on the same inclined plane. The ratio of the acceleration of the cylinder '$a_c$' to that of sphere '$a_s$' is

When a monochromatic ray of light is passed through an equilateral glass prism, it is found that the refracted ray in glass is parallel to the base of the prism. If '$i$' and '$e$' denote the angles of incidence and emergence respectively, then}

A wire $PQ$ has length $4.8\text{ m}$ and mass $0.06\text{ kg}$. Another wire $QR$ has length $2.56\text{ m}$ and mass $0.2\text{ kg}$. Both wires have same radii and are joined as a single wire. This wire is under tension of $80\text{ N}$. A wave pulse of amplitude $3.5\text{ cm}$ is sent along the wire $PQ$ from end $P$. The time taken by the wave pulse to travel along the wire from point $P$ to $R$ is?

A sonometer wire 49 cm long is in unison with a tuning fork of frequency '$n$'. If the length of the wire is decreased by 1 cm and it is vibrated with the same tuning fork, 6 beats are heard per second. The value of '$n$' is

An alternating voltage $E = 200\sqrt{2} \sin(100t)$ volt is connected to a $1 \mu\text{F}$ capacitor through an a.c. ammeter. The reading of the ammeter shall}

The self induction ($L$) produced by solenoid of length '$l$' having '$N$' number of turns and cross sectional area '$A$' is given by the formula ($\phi = \text{magnetic flux through one turn}, \mu_0 = \text{permeability of vacuum}$)}

When moving coil galvanometer (MCG) is converted into a voltmeter, the series resistance is '$n$' times the resistance of galvanometer. How many times that of MCG the voltmeter is now capable of measuring voltage?

At constant temperature, increasing the pressure of a gas by $5%$ its volume will decrease by}

Half life of radio-active element is $1600$ years. The fraction of sample remains undecayed after $6400$ years will be

A long wire is bent into a circular coil of one turn and then into a circular coil of smaller radius having $n$ turns. If the same current passes in both the cases, the ratio of magnetic fields produced at the centre for one turn to that of $n$ turns is

Figure shows two semicircular loops of radii $R_1$ and $R_2$ carrying current $I$. The magnetic field at the common centre '$O$' is

A coil having effective area $A$, is held with its plane normal to magnetic field of induction $B$. The magnetic induction is quickly reduced by $25%$ of its initial value in $2$ second. Then the e.m.f. induced across the coil will be

When the conductivity of a semiconductor is only due to the breaking of the covalent bonds, the semiconductor is called}

In an $n-p-n$ transistor, the collector current is $28$ mA. If $80%$ of electrons reach the collector, its base current in mA is

The position '$x$' of a particle varies with a time as $x = at^2 - bt^3$ where '$a$' and '$b$' are constants. The acceleration of the particle will be zero at}

A light spring is suspended with mass $m_1$ at its lower end and its upper end fixed to a rigid support. The mass is pulled down a short distance and then released. The period of oscillation is $T$ second. When a mass $m_2$ is added to $m_1$ and the system is made to oscillate, the period is found to be $\frac{3}{2}T$. The ratio $m_1 : m_2$ is

Two condensers one of capacity $\frac{C}{2}$ and other capacity $C$ are connected to a battery of voltage $V$ as shown. The work done in charging fully both the condensers is

Earth is assumed to be a sphere of radius $R$. If '$g_{\phi}$' is value of effective acceleration due to gravity at latitude $30^{\circ}$ and '$g$' is the value at equator, then the value of $|g - g_{\phi}|$ is ($\omega$ is angular velocity of rotation of earth, $\cos 30^{\circ} = \frac{\sqrt{3{2}$ )}

Four identical uniform solid spheres each of same mass '$M$' and radius '$R$' are placed touching each other as shown in figure, with centres $A$, $B$, $C$, $D$. $I_A$, $I_B$, $I_C$ and $I_D$ are the moment of inertia of these spheres respectively about an axis passing through centre and perpendicular to the plane. The difference in $I_A$, and $I_B$ is

Refractive index of a glass convex lens is $1.5$. The radius of curvature of each of the two surfaces of the lens is $20 \text{ cm}$. The ratio of the power of the lens when immersed in a liquid of refractive index $1.25$ to that when placed in air is

When two light waves each of amplitude '$A$' and having a phase difference of $\frac{\pi}{2}$ superimposed then the amplitude of resultant wave is

A parallel plate capacitor with air medium between the plates has a capacitance of $10 \mu\text{F}$. The area of capacitor is divided into two equal halves and filled with two media (as shown in figure) having dielectric constant $K_1 = 2$ and $K_2 = 4$. The capacitance of the system will be

A metal rod cools at the rate of $4^\circ\text{C}/\text{min}$ when its temperature is $90^\circ\text{C}$ and the rate of $1^\circ\text{C}/\text{min}$ when its temperature is $30^\circ\text{C}$. The temperature of the surrounding is