List of top Physics Questions

Half-life of radon is 3.5 days. The amount of radon left out of 12 mg mass undecayed after 35 days is nearly
The velocity of a travelling plane wave given by \[ y = 10^{-2} \sin \left( 200t - \frac{x}{5} \right) m, \] is
The energy stored in a soap bubble of diameter 4 cm is nearly (surface tension of soap solution is 0.07 N/m)
Two perfectly black bodies are at temperatures \( T \) and \( 2T \). The ratio between the wavelengths corresponding to maximum energy emission by the two black bodies is
A projectile is given an initial velocity of $(\hat{i} + \hat{j})$ m/s, where $\hat{i}$ is along the ground and $\hat{j}$ is along the vertical direction. The equation of its trajectory is $(g = 10 \, \text{m/s}^2)$.
The magnetic force acting on a charged particle carrying a charge $3 \mu C$ in a magnetic field of $5$ T acting in the $y$-direction, when the particle velocity is \[ (\hat{i} + \hat{j}) \times 10^5 { ms}^{-1} \] is
A particle is describing a uniform circular motion with a certain constant speed. The INCORRECT statement is
The gravitational potential energy of a system of two bodies each of mass $m$ and distance $r$ between them is (G = gravitational constant, g = acceleration due to gravity)
In a p-n junction diode, reverse biasing
Which one of the following is not a semiconductor?
A particle moves under the influence of a force in the XY-plane such that the components of its linear momentum $\vec{p}$ at any time $t$ are given by $p_x = p \sin t$ and $p_y = p \cos t$. The angle between $\vec{F}$ and $\vec{p}$ at that time is
A block of mass $M$ moves with a velocity $v$ along a frictionless horizontal surface towards another block of mass $2M$ at rest. The velocity of the center of mass of the system of blocks is
When two different liquids of same mass but at two different temperatures \(27^\circ C\) and \(47^\circ C\) are mixed together, the resulting temperature of the mixture is \(35^\circ C\). The ratio of their specific heat capacities is
If $P$ is the pressure at which the heart is pumping the blood and the volume of blood pumped per second is $V$, then the power of the heart is given by
A parallel plate capacitor with a dielectric medium of dielectric constant 1.5 has a capacitance of \(C\). If the dielectric is removed, then the capacitance of the capacitor becomes
When water is heated from $0^\circ$C to $8^\circ$C, its volume
The pressure of an ideal gas is proportional to the cube of its temperature (on absolute scale) in an adiabatic process. Then the value of the ratio $C_p/C_v$ is
The radius of gyration of a regular solid cylinder of radius $R$ about its axis is
The number of significant figures in 0.0500L is
When two spheres of radii $r$ and $\frac{r}{2}$ are brought in contact, the gravitational force of attraction between them is proportional to
An ink mark is made on a piece of paper and a glass slab of thickness $t$ and refractive index $\mu$ is placed on it. If the image of the ink mark appears to be at a distance of $x$ from the top surface of the slab, then the value of $x$ is
If the ratio of amplitudes of two light waves is 2 : 1, then the ratio between the intensities of the two waves is

In Young’s double slit experiment, to change the bandwidth from $\beta$ to $\frac{\beta}{4}$ without changing the experimental setup, the wavelength of light $\lambda$ used must be changed to

For a paramagnetic material, the magnetic susceptibility \( \chi_m \) is
The photoelectric work function for a photosensitive material is 5.2 eV. The energy of the incident radiation for which the stopping potential is 6 V is