List of top Physics Questions

For an exothermic reaction, the value of:

For a Carnot engine, the source is at $500\, K$ and the sink at $300\, K$. What is efficiency of this engine?

According to Heisenberg's uncertainty principle, the product of uncertainties in position and velocities for an electron of mass $ 9.1\times {{10}^{-31}}\,kg $ is:

Escape velocity at surface of earth is $11.2\,km/s$. Escape velocity from a planet whose mass is the same as that of earth and radius $1/4$ that of earth, is :

A $100\, m$ long train is moving with a uniform velocity of $45\, km/h$. The time taken by the train to cross a bridge of length $1\, km$ is:

Velocity-time curve for a body, projected vertically upwards, is:

The frequency of vibration of string is given by $ v=\frac{P}{2l}{{\left[ \frac{F}{m} \right]}^{1/2}} $ Here $ p $ is number of segments in the string and $l$ is the length. The dimensional formula for $ m $ will be:

A ball of mass $150\,g$ moving with an acceleration $20 \,m/s^2$ is hit by a force, which acts on it for $0.1\, s$. The impulsive force is :

A cylinder of mass $10 \,kg$ is rolling on a rough plane with a velocity of $10 \,m/s$. If the coefficient of friction between the surface and cylinder is $0.5$, then before stopping it will cover a distance of (Take $g = 10\, m/s^2$):

What is the value of linear velocity, if angular velocity is $3 \hat i - 4 \hat j + \hat k$ and distance from the centre is $5 \hat i - 6 \hat j + 6 \hat k$ ?

Figure shows a body of mass m moving with a uniform speed $v$ along a circle of radius $r$. The change in velocity in going from $A$ to $B$ is:

What is the value of linear velocity, if angular velocity is $3 \hat i - 4 \hat j + \hat k$ and distance from the centre is $5 \hat i - 6 \hat j + 6 \hat k$ ?

The angular momentum of a system of particles is not conserved :

Figure shows a body of mass m moving with a uniform speed $v$ along a circle of radius $r$. The change in velocity in going from $A$ to $B$ is:

A square wire frame of size $L$ is dipped in a liquid. On taking out, a membrane is formed. If the surface tension of liquid is $T$, the force acting on the frame will be :

Angular width $ (\theta ) $ of central maximum of a diffraction pattern of a single slit does not depend upon:

The first overtone of a stretched wire of given length is $320 \,Hz$. The first harmonic is :

Two identical conducting rods are first connected independently to two vessels, one containing water at 100$^{\circ}$C and the other containing ice at 0$^{\circ}$C. In the second case, the rods are joined end to end and connected to the same vessels. Let q$_1$ and q$_2$ gram per second be the rate of melting of ice in the two cases respectively. The ratio $\frac{q_1}{q_2}$ is

A black body at $200\, K$ is found to exit maximum energy at a wavelength $14\, \mu\, m$ When its temperature is raised to $1000\, K$, then wavelength at which maximum energy emitted is

The electric potential at the surface of an atomic nucleus $(Z=50)$ of radius $9.0 \times 10^{-13} cm$ is

One milligram of matter converted into energy, will give

The capacity of a condenser is $4 \times 10^{-6} F$ and its potential is $100\, V$. The energy released on discharging it fully will be

The half-life of radium is $1620\, yr$ and its atomic weight is $226\, kg$ per kilomol. The number of atoms that will decay from its $1\, g$ sample per second will be (Avogadro's number $N=6.023 \times 10^{23}$ atoms/ $mol$ )

$20 \,A$ current is flowing in a long straight wire. The intensity of magnetic field at a distance of $10\, cm$ from the wire, will be

An electron having charge $1.6 \times 10^{-19} C$ and mass $9 \times 10^{-31} kg$ is moving with $4 \times 10^{6} m / s$ speed in a magnetic field of $2 \times 10^{-1} T$ in a circular orbit. The force acting on an electron and the radius of circular orbit will be