List of top Physics Questions

At what temperature the root mean square velocity of a gas is twice of its root mean velocity at $27^{\circ} C $?
In a triode, $\mu, g_{m}$ and $r_{p}$ are related as
$120\, AC$ voltage is applied to $10$ ohm resistance. The peak voltage across the resistor is
The average kinetic energy of a molecule of a gas at absolute temperature T is propor tional to
The following four gases are at the same temperature. In which gas do the molecules have the maximum root mean square speed?
If k is the Boltzmann cottstant, the average kinetic energy of a gas molecule at absolute temperature T is
At a given temperature if $V_{rms}$ is the root mean square velocity of the molecules of a gas and $V_s$ be the velocity of sound in it, then these are related as $\left(\gamma = \frac{C_p}{C_v}\right)$
The heat required to raise the temperature of one mole of gas by 1$^\circ$C at constant volume is $k$ times that required to raise the temperature of one mole of triatomic gas at constant pressure. What is the value of $k$ ?
Statement 1. Boyle's law is independent of the selection of scale of temperature.$\,$ Statement 2. Boyle's law does not hold good for a gas at low temperature and high pressure.
The relation between volume V, pressure P and absolute temperature T of an ideal gas is $PV = x T$ where x is a constant The value of x depends upon
$1$ unified atomic mass unit $(1 \,u)$ is equal to
$ 1 $ kilowatt hour $ (kWh) $ is equal to
A ball of mass $m$ moving with a speed v makes a head on collision with an identical ball at rest. The kinetic energy after collision of the balls is three fourth of the original kinetic energy. The coefficient of restitution is
A sliding rod $AB$ of resistance $R$ is shown in figure. Here magnetic field $B$ is constant and is out of the paper Parallel wires have no resistance and the rod is moving with constant velocity $v$. The current in the sliding rod $AB$ when switch $S$ is closed at time $t =0$ is
A metal plate can be heated by
1 henry =
The potential across a generator is 125V when it is delivering 10A. When it delivers 30A the potential is 120V. What are the resistance of armature and induced e.m.f. ?
A metallic rod of $1 \,m$ length is rotated with a frequency of $50$ revolution per second, with one end hinged at the centre and the other end at the circumference of a circular metallic ring of radius $1\, m$ about an axis passing through the centre and perpendicular to the plane of the ring. $A $ constant uniform magnetic field of $1 \,T$ parallel to the axis is present everywhere. The emf between the centre and the metallic ring is
A black body at $1373$ $?$ emits maximum energy corresponding to a wavelength of $1.78$ microns. The temperature of the moon for which $\lambda _{m}=14$ micron would be
Three rods made from the same material and having the same cross-sectional area, form the sides of an isosceles triangle $ABC$ , right-angled at $B$ . The points $A$ and $B$ are maintained at temperature $T$ and $\sqrt{2}T$ , respectively. In steady-state, the temperature of the point $C$ is $T_{C}$ . Assuming that only heat conduction takes place along the lengths of the rods, the value of $\frac{T_{C}}{T}$ is
A hollow flask retains its shape on heating because
A wall is made of equally thick layers $A$ and $B$ of different materials. Thermal conductivity of $A$ is twice that of $B$. In the steady state, the temperature difference across the wall is $36^{\circ}C$. The temperature difference across the layer $A$ is
The radiation emitted by a star $A$ is $10,000$ times that of the sun. If the surface temperatures of the sun and the star $A$ are $8000 \, K$ and $2000 \, K$ respectively. The ratio of the radii of the star $A$ and the sun is
An equilateral triangle $ABC$ is cut from a thin solid sheet of wood. (See figure) $D, \, E$ and $F$ are the mid-points of its sides as shown and $G$ is the centre of the triangle. The moment of inertia of the triangle about an axis passing through $G$ and perpendicular to the plane of the triangle is $I_{0}$ . If the smaller triangle $DEF$ is removed from $ABC,$ the moment of inertia of the remaining figure about the same axis is $I.$ Then:
A wheel of the radius $0.4 \, m$ can rotate freely about its axis. A string is wrapped over its rim and a mass of $4 \, kg$ is hung. An angular acceleration of $8 \, rad \, s^{- 2}$ is produced in it due to the torque. Then, the moment of inertia of the wheel is ( $g=10 \, m \, s^{- 2}$ )