List of top Physics Questions asked in JEE Main

Consider a cylinder of mass $M$ resting on a rough horizontal rug that is pulled out from under it with acceleration $'a'$ perpendicular to the axis of cylinder. What is $F_{friction}$ at point $P$ ? It is assumed that the cylinder does not slip.

During the propagation of electromagnetic waves in a medium,

Figure shows a circular area of radius R where a uniform magnetic field $\vec{B}$ is going into the plane of paper and increasing in magnitude at a constant rate. In that case, which of the following graphs, drawn schematically, correctly shows the variation of the induced electric field E(r)?

For sky wave propagation, the radio waves must have a frequency range in between :

Four particles, each of mass M and equidistant from each other, move along a circle of radius R under the action of their mutual gravitational attraction, the speed of each particle is

From a tower of height $H$, a particle is thrown vertically upwards with a speed $u$. The time taken by the particle to hit the ground, is $n$ times that taken by it to reach the highest point of its path. The relation between $H, u$ and $n$ is

In a large building, there are 15 bulbs of 40\, W, 5 bulbs of 100 W, 5 fans of $80\, W$ and 1 heater of $1\, kW$. The voltage of the electric mains is $220 \,V$. The minimum capacity of the main fuse of the building will be :

In materials like aluminium and copper, the correct order of magnitude of various elastic modulii is :

In the circuit shown, current (in A) through the 50 V and 30 V batteries are, respectively :

When a rubber -band is stretched by a distance x, it exerts a restoring force of magnitude $ F = ax + bx^2$, where a and b are constants. The work done in stretching the unstretched rubber-band by $L$ is :

When the rms voltages $V _{ L }, V _{ C }$ and $V _{ R }$ are measured respectively across the inductor $L ,$ the capacitor $C$ and the resistor $R$ in a series LCR circuit connected to an AC source, it is found that the ratio $V _{ L }: V _{ C }: V _{ R }=1: 2: 3$. If the rms voltage of the AC sources is $100 \,V ,$ the $V _{ R }$ is close to:

Three rods of copper , brass and steel are welded together to form a Y-shaped structure .Area of cross -section of each rod is $4cm^2$.End of copper rod is maintained at $100^{\circ}C$ whereas ends of brass and steel are kept at $0^{\circ C}$ Lengths of the copper, brass and steel rods are 46,13 and 12 cm respectively The rods are thermally insulated from surroundings except at ends.Thermal conductivities of copper , brass and steel are 092 , 0.26 and 0.12 in CGS units , respectively .Rate of heat flow throught cooper rod is

On heating water, bubbles being formed at the bottom of the vessel detatch and rise. Take the bubbles to be spheres of radius $R$ and making a circular contact of radius r with the bottom of the vessel. If $r << R$, and the surface tension of water is T, value of r just before bubbles detatch is (density of water is $\rho_{w}$ )

Steel ruptures when a shear of $ 3.5 \times 10^8 \,Nm^{-2}$ is applied. The force needed to punch a $1\, cm$ diameter hole in a steel sheet $0.3\, cm$ thick is nearly :

The angular frequency of the damped oscillator is given by, $\omega = \sqrt{\left(\frac{k}{m} - \frac{r^{2}}{4m^{2}}\right)}$ where $k$ is the spring constant, $m$ is the mass of the oscillator and $r$ is the damping constant. If the ratio $\frac{r^{2}}{mk}$ is $8\%$, the change in time period compared to the undamped oscillator is approximately as follows :

The gap between the plates of a parallel plate capacitor of area A and distance between plates $d$, is filled with a dielectric whose permittivity varies linearly from $\epsilon_{1}$ at one plate to $\epsilon_{2}$ at the other. The capacitance of capacitor is :

The space between the plates of a parallel plate capacitor is filled with a 'dielectric' whose 'dielectric constant' varies with distance as per the relation : $K\left(x\right)=K_{0}+\lambda x\left(\lambda=a\,\text{constant}\right)$ The capacitance $C$, of this capacitor, would be related to its 'vacuum' capacitance $C_o$ as per the relation :

There is a circular tube in a vertical plane. Two liquids which do not mix and of densities $d_1$ and $d_2$ are filled in the tube. Each liquid subtends $90^\circ$ angle at centre. Radius joining their interface makes an angle a with vertical. Ratio $\frac{d_{1}}{d_{2}}$ is :

Two beams, A and B, of plane polarised light with mutually perpendicular planes of polarisation are seen through a Polaroid. From the position when the beam A has maximum intensity (and beam B has zero intensity), a rotation of Polaroid through 30$^{\circ}$ makes the two beams appear equally bright. If the initial intensities of the two beams are $I_A \, and \, I_B$ respectively, then $I_A / I_B$ equals

Match List -1 (Electromagnetic wave type) with List - II (Its association/application) and select the correct option from the choices given below the lists :

Parallel rays of light of intensity I=912 Wm$^{-2}$ are incident on a spherical black body kept in surroundings of temperature 300 K . Take Stefan constant $\sigma =5.7 \times 1^{-8} Wm ^{-2} K^{-4}$ and assume that the energy exchange with the surroundings is only through radiation The final steady state temperature of the black body is close to

The total length of a sonometer wire between fixed ends is $110\, cm$. Two bridges are placed to divide the length of wire in ratio $6 : 3 : 2$. The tension in the wire is $400\, N$ and the mass per unit length is $0.01\, kg/m$. What is the minimum common frequency with which three parts can vibrate ?

Which of the following modulated signal has the best noise-tolerance ?

In an experiment on photoelectric effect, a student plots stopping potential \(V_0\) against reciprocal of the wavelength \(\lambda\) of the incident light for two different metals A and B. These are shown in the figure.

Looking at the graphs, you can most appropriately say that:

A copper ball of radius 1 cm and work function 4.47 eV is irradiated with ultraviolet radiation of wavelength 2500 \(\mathrm{\AA}\). The effect of irradiation results in the emission of electrons from the ball. Further the ball will acquire charge and due to this there will be a finite value of the potential on the ball. The charge acquired by the ball is :