List of top Physics Questions

A physical quantity $P$ is described by the relation $P = a^{1/2} b^2 c^3 d^{-4} $ If the relative errors in the measurement of $a, b, c$ and $d$ respectively, are $2\%, 1\%, 3\%$ and $5\%$, then the relative error in $P$ will be :
The energy stored in the electric field produced by a metal sphere is $4.5\, J$. If the sphere contains $ 4 \, \mu C$ charge, its radius will be : [Take : $\frac{1}{4 \pi \epsilon_o } = 9 \times 10^{9} \, N - m^2 / C^2$ ]
The current gain of a common emitter amplifier is $69$ . If the emitter current is $7.0 \,mA$, collector current is :
$2$ moles of an ideal monatomic gas is carried from a state $(P_0, V_0)$ to a state $(2P_0, 2V_0)$ along a straight line path in a P-V diagram. The amount of heat absorbed by the gas in the process is given by
The semi-major axis of the orbit of Saturn is approximately nine times that of Earth. The time period of revolution of Saturn is approximately equal to
A metre scale made of steel reads accurately at $25^{\circ} C$ . Suppose in an experiment an accuracy of $0.06\, mm$ in $1\,m$ is required, the range of temperature in which the experiment can be performed with this metre scale is (coefficient of linear expansion of steel is $ 11 \times 10^{-6} /^{\circ} \, C$ )
A thermocol box has a total wall area (including the lid) of $1.0 m ^{2}$ and wall thickness of $3 cm$. It is filled with ice at $0^{\circ} C$. If the average temperature outside the box is $30^{\circ} C$ throughout the day, the amount of ice that melts in one day is [Use $K_{\text {thermocol }}=0.03 W / mK$ $.L_{\text {fusion (ice) }}=3.00 \times 10^{5} J / kg ]$
A parallel beam of light of intensity \(I_0\) is incident on a coated glass plate. If \(25\%\) of the incident light is reflected from the upper surface and \(50\%\) of light is reflected from the lower surface of the glass plate, the ratio of maximum to minimum intensity in the interference region of the reflected light is
A wooden box lying at rest on an inclined surface of a wet wood is held at static equilibrium by a constant force $F$ applied perpendicular to the incline. If the mass of the box is $1\,kg$, the angle of inclination is $30^{\circ}$ and the coefficient of static friction between the box and the inclined plane is $0.2$, the minimum magnitude of $\vec{F}$ is (Use $ g = 10\,m/s^2$)
Consider a solenoid carrying current supplied by a DC source with a constant emf containing iron core inside it. When the core is pulled out of the solenoid, the change in current will
Which of the following principles is being used in Sonar Technology ?
A planet of mass $m$ moves in an elliptical orbit around an unknown star of mass $M$ such that its maximum and minimum distances from the star are equal to $r_1$ and $r_2$ respectively. The angular momentum of the planet relative to the centre of the star is
Which of the following is emitted when $^{239}_{94} Pu$ decays into $^{235}_{92}U$ ?
An AC generator producing 10V(rms) at 200 rad/s is connected in series with a $50 \Omega$ resistor, a 400 mH inductor and a $200 \mu F$ capacitor. The rms voltage across the inductor is
A wire has resistance of $3.1 \,\Omega $ at $30^{\circ} \, C$ and $4.5\, \Omega $ at $100^{\circ} C$ . The temperature coefficient of resistance of the wire is
An electron collides with a Hydrogen atom in its ground state and excites it to $n = 3$ state. The energy given to the Hydrogen atom in this inelastic collision (neglecting the recoil of Hydrogen atom) is
An object is thrown vertically upward with a speed of $30\, m/s$. The velocity of the object half-a-second before it reaches the maximum height is
A body initially at 80$^{\circ}$C cools to 64$^{\circ}$C in 5 min and to 52$^{\circ}$C in 10 min. The temperature of the surrounding is
A ceiling fan rotates about its own axis with some angular velocity. When the fan is switched off, the angular velocity becomes $(\frac{1}{4})^{th}$ of the original in time ?t? and ?n? revolutions are made in that lime. The number of revolutions made by the fan during the time interval between switch off and rest are (Angular retardation is uniform)
Electromagnetic waves transport
What is the net charge if a certain semiconductor losses 4 valence electrons?
If the feedback fraction of an amplifier is 0.01, then voltage gain with negative feedback is approximately ____
The time interval between two event in a reference frame which is in motion is
Special theory of relativity treats problem involving
The nucleus which is an isotope of C117 and also an isobar of Ar18 has mass number A and atomic number Z given by ______