List of top Physics Questions asked in JEE Main

A spherical drop of liquid splits into 1000 identical spherical drops If $u _{ i }$ is the surfice energy of the original drop and $u_f$ is the total surface energy of the resulting drops, the (ignoring evaporation), $\frac{u_f}{u_i}=\left(\frac{10}{x}\right)$ Then value of $x$ is ___

An object of mass 'm' initially at rest on a smooth horizontal plane starts moving under the action of force $F=2 N$ In the process of its linear motion, the angle $\theta$ (as shown in figure) between the direction of force and horizontal varies as $\theta=k x$, where $k$ is a constant and $x$ is the distance covered by the object from its initial position The expression of kinetic energy of the object will be $E=\frac{n}{k} \sin \theta$ The valte of $n$ is

An object of mass m initially at rest on a smooth horizontal plane starts moving

In an ac generator, a rectangular coil of $100$ turns each having area $14 \times 10^{-2} m ^2$ is rotated at $360\, rev / min$ about an axis perpendicular to a uniform magnetic field of magnitude $3.0 T$ The maximum value of the emf produced will be ________ $V$
(Take $\pi =\frac{22}{7}$)

A radioactive nucleus decays by two different process The half life of the first process is 5 minutes and that of the second process is $30 s$. The effective half-life of the nucleus is calculated to be $\frac{\alpha}{11}$ s The value of $\alpha$ is _______

A nucleus disintegrates into two smaller parts, which have their velocities in the ratio $3: 2$ The ratio of their nuclear sizes will be $\left(\frac{x}{3}\right)^{\frac{1}{3}}$ The value of ' $x$ ' is:-

In a Young's double slit experiment, the intensities at two points, for the path respectively If $I_0$ denotes the intensity produced by each one of the individual slits, then $\frac{I_1+I_2}{I_0}=$_______

A capacitor has capacitance $5 \mu F$ when it's parallel plates are separated by air medium of thickness d A slab of material of dielectric constant $15$ having area equal to that of plates but thickness $\frac{d}{2}$ is inserted between the plates Capacitance of the capacitor in the presence of slab will be ___$\mu F$

In a screw gauge, there are 100 divisions on the circular scale and the main scale moves by $0.5 \,mm$ on a complete rotation of the circular scale The zero of circular scale lies $6$ divisions below the line of graduation when two studs are brought in contact with each other When a wire is placed between the studs, $4$ linear scale divisions are clearly visible while $46^{\text {th }}$ division the circular scale coincide with the reference line The diameter of the wire is _____$\times 10^{-2} mm$

In an experiment for estimating the value of focal length of converging mirror, image of an object placed at $40\, cm$ from the pole of the mirror is formed at distance $120 \,cm$ from the pole of the mirror These distances are measured with a modified scale in which there are $20$ small divisions in $1 \,cm$ The value of error in measurement of focal length of the mirror is $\frac{1}{ K } cm$ The value of $K$ is ______

A thin uniform rod of length $2 m$, cross sectional area ' $A$ ' and density ' $d$ ' is rotated about an axis passing through the centre and perpendicular to its length with angular velocity $\omega$ If value of $\omega$ in terms of its rotational kinetic energy $E$ is $\sqrt{\frac{\alpha Ad }{ Ad }}$ then value of $\alpha$ is _____

As shown in the figure, In an experiment to determine Young's modulus of a wire the extension-load curve is plotted. The curve is a straight line passing through the origin and makes an angle of $45^{\circ}$ with the load axis The length of wire is $628 \,cm$ and its diameter is $4 \,mm$ The Young's modulus is found to be $x \times 10^4 Nm ^{-2}$The value of $x$ is

The general displacement of a simple harmonic oscillator is $x= A\sin\omega t$. Let $T$ be its time period The slope of its potential energy $(U)$ - time (t) curve will be maximum when $t=\frac{T}{\beta}$ The value of $\beta$ is

As per the given figure, if $\frac{ dI }{ dt }=-1 A /$ s then the value of $V _{ AB }$ at this instant will be ______$V$

A capacitor of capacitance $900\, \mu F$ is charged by a $100\, V$ battery The capacitor is disconnected from the battery and connected to another uncharged identical capacitor such that one plate of uncharged capacitor connected to positive plate and another plate of uncharged capacitor connected to negative plate of the charged capacitor The loss of energy in this process is measured as $x \times 10^{-2} J$ The value of $x$ is ______

A horse rider covers half the distance with $5\, m / s$ speed The remaining part of the distance was travelled with speed $10\, m / s$ for half the time and with speed $15\, m / s$ for other half of the time The mean speed of the rider averaged over the whole time of motion is $\frac{x}{7} m / s$ The value of $x$ is _____

The surface of water in a water tank of cross section area $750 \, \text{cm}^2$ on the top of a house is $h \, \text{m}$ above the tap level. The speed of water coming out through the tap of cross section area $500 \, \text{mm}^2$ is $30 \, \text{cm/s}$. At that instant, $\frac{dh}{dt}$ is $x \times 10^{-3} \, \text{m/s}$. The value of $x$ will be _________.

A charge particle of $2 \,\mu C$ accelerated by a potential difference of $100\, V$ enters a region of uniform magnetic field of magnitude $4 \,mT$ at right angle to the direction of field The charge particle completes semicircle of radius $3 \,cm$ inside magnetic field The mass of the charge particle is _______ $\times 10^{-18} kg$

For a train engine moving with speed of $20\, ms ^{-1}$, the driver must apply brakes at a distance of 500 $m$before the station for the train to come to rest at the station. If the brakes were applied at half of this distance, the train engine would cross the station with speed $\sqrt{x} ms ^{-1}$. The value of $x$ is ________ . (Assuming same retardation is produced by brakes)

A cubical volume is bounded by the surfaces $ x = 0 $, $ x = a $, $ y = 0 $, $ y = a $, $ z = 0 $, $ z = a $. The electric field in the region is given by: \[ \vec{E} = E_0 x \hat{i} \]
Where $ E_0 = 4 \times 10^4 \, \text{NC}^{-1} \, \text{m}^{-1} $. If $ a = 2 \, \text{cm} $, the charge contained in the cubical volume is $ Q \times 10^{-14} \, \text{C} $. The value of $ Q $ is ______. (Take $ \epsilon_0 = 9 \times 10^{-12} \, \text{C}^2/\text{Nm}^2 $)

In the given circuit, the value of $\left|\frac{I_1+I_3}{I_2}\right|$ is ___.

A square-shaped coil of area $70 \, \text{cm}^2$ having 600 turns rotates in a magnetic field of $0.4 \, \text{wbm}^{-2}$, about an axis which is parallel to one of the sides of the coil and perpendicular to the direction of the field. If the coil completes 500 revolutions in a minute, the instantaneous emf when the plane of the coil is inclined at $60^\circ$ with the field, will be ________ V. (Take $\pi = \frac{22}{7}$)

A block is fastened to a horizontal spring. The block is pulled to a distance $x=10\ cm$ from its equilibrium position (at $x=0$ ) on a frictionless surface from rest. The energy of the block at $x=5$ $cm$ is $025 J$. The spring constant of the spring is _____$Nm ^{-1}$.

As shown in the figure, in Young’s double slit experiment, a thin plate of thickness $t = 10 \, \mu\text{m}$ and refractive index $\mu = 1.2$ is inserted in front of slit $S_1$. The experiment is conducted in air ($\mu = 1$) and uses a monochromatic light of wavelength $\lambda = 500 \, \text{nm}$. Due to the insertion of the plate, central maxima is shifted by a distance of $x \beta_0$. $\beta_0$ is the fringe-width before the insertion of the plate. The value of $x$ is _________.

A force $F =\left(5+3 y^2\right)$ acts on a particle in the $y$-direction, where $F$ is in newton and $y$ is in meter The work done by the force during a displacement from $y=2 m$ to $y=5 m$ is___ $J$.

Moment of inertia of a disc of mass $M$ and radius $R$ about any of its diameters is $\frac{MR^2}{4}$. The moment of inertia of this disc about an axis normal to the disc and passing through a point on its edge will be, $\frac{x}{2}MR^2$. The value of $x$ is _________.