List of top Physics Questions asked in JEE Main

Choose correct option :
(A) Number of photons required for a light beam of 2000 pm wavelength and 1 Joule energy is \(1.01 \times 10^{16}\).
(B) Light with wavelength 300 nm has energy \(E_1\) and for wavelength 900 nm has energy \(E_2\), then \(E_1/E_2 = 1/3\).
(C) Frequency of light is \(4.5 \times 10^{16}\) Hz then its wavelength is \(6.7 \times 10^{-9}\) m.
(D) If electrons and protons are accelerated by same potential difference, then their de-Broglie wavelength are equal.

Two spheres having equal mass \( m \), charge \( q \), and radius \( R \), are moving towards each other. Both have speed \( u \) at an instant when the distance between their centers is \( 4R \). Find the minimum value of \( u \) so that they touch each other.

A particle starts moving from time \(t=0\) and its coordinate is given as \[ x(t)=4t^3-3t. \] Consider the following statements:
[A.] The particle returns to its original position (origin) \(0.866\) units later.
[B.] The particle is \(1\) unit away from origin at its turning point.
[C.] Acceleration of the particle is non-negative.
[D.] The particle is \(0.5\) units away from origin at its turning point.
[E.] The particle never turns back as acceleration is non-negative.
Choose the correct answer from the options given below:

A wave propagates whose electric field is given by \[ \vec{E} = 69 \sin(\omega t - kx)\,\hat{j}. \] Find the direction of the magnetic field.

There are two point charges, one at the vertex and the other at the face of a cube as shown. Find the electric flux through the cube.

If resistance between \(A\) and \(C\) is increased by \(10%\) through heating, then calculate \(|V_A - V_B|\).

For an object revolving around a planet of mass \( M \) and radius \( R_0 \) at a distance \( r \) from the center of the planet. If area velocity of the object is 10 km/sec. Now if the density of the planet increases by +10% and radius of the planet increases by +10%, then find the new area velocity at the same orbital radius.

A set of measurements of a certain parameter is: $20.00,\; 19.75,\; 18.25,\; 17.01$. Find the relative error for the set of measurements.

A planet 'A' having density \( \rho \) and radius \( R \) has escape velocity \( = 10 \, \text{km/sec} \). Find the escape velocity of a planet B having density and radius both 10% that of planet A.

A rod of mass \(m\) and length \(L\) is released on a rail placed in a uniform magnetic field \(B\) as shown. The circuit has resistance \(R\). What will be the terminal velocity of the rod? v

A \(12\,\text{F}\) capacitor is connected to a \(5\,\text{V}\) battery and fully charged. After disconnecting the battery, it is connected in parallel to an uncharged \(6\,\text{F}\) capacitor. Find the final charge on the \(6\,\text{F}\) capacitor.

Match the following as per dimensional formula.

When the position vector \[ \vec r = x\hat{i}+y\hat{j}+z\hat{k} \] changes sign as \(\vec r \rightarrow -\vec r\), which one of the following vectors will {not flip under sign change?}

A long cylindrical conductor with large cross section carries an electric current distributed uniformly over its cross-section. Magnetic field due to this current is:
[A.] maximum at either end of the conductor
[B.] maximum at the axis of the conductor and minimum at the midpoint
[C.] minimum at the surface of the conductor
[D.] minimum at the axis of the conductor
[E.] same at all points in the cross-section of the conductor
Choose the correct answer from the options given below:

Suppose a long solenoid of 100 cm length, radius 2 cm having 500 turns per unit length, carries a current $I = 10 \sin (\omega t)$ A, where $\omega = 1000$ rad./s. A circular conducting loop (B) of radius 1 cm coaxially slided through the solenoid at a speed $v = 1$ cm/s. The r.m.s. current through the loop when the coil B is inserted 10 cm inside the solenoid is $\alpha / \sqrt{2} \mu A$. The value of $\alpha$ is ___. [Resistance of the loop = 10 $\Omega$]

What will be the ratio of the wavelength of the 3rd line of the Paschen Series to the 2nd line of the Balmer series of H-atom?

The pulley shown in figure is made using a thin rim and two rods of length equal to diameter of the rim. The rim and each rod have a mass of $M$. Two blocks of mass of $M$ and $m$ are attached to two ends of a light string passing over the pulley, which is hinged to rotate freely in vertical plane about its center. The magnitudes of the acceleration experienced by the blocks is _________ (assume no slipping of string on pulley).

The exit surface of a prism with refractive index $n$ is coated with a material having refractive index $\dfrac{n}{2}$. When this prism is set for minimum angle of deviation, it exactly meets the condition of critical angle. The prism angle is ___.

A curve is given between the potential energy \(U\) of a particle and its position on the \(x\)-axis as shown. Given: \[ \tan\theta_1 = 1,\qquad \tan\theta_2 = 3,\qquad \tan\theta_3 = -\frac{1}{2} \] If \(F_{AB}\) is the force acting on the particle during motion from \(A\) to \(B\), similarly \(F_{BC}\), \(F_{CD}\) and \(F_{DE}\) are the forces during \(B\) to \(C\), \(C\) to \(D\) and \(D\) to \(E\) respectively, arrange the magnitudes of these forces in decreasing order.

Light is incident at such an angle so that minimum deviation takes place. Now a film of refractive index RI = \(n/2\) is stick on other face such that total internal reflection takes place on second surface. Find angle of prism :

As shown in the figure, six rods of same geometry are connected and maintained at temperatures \(100^\circ\text{C}\) and \(40^\circ\text{C}\). The temperature at points \(A\) and \(B\) are:

A soap bubble of diameter $7$ cm, its diameter is increased to $14$ cm. If change in its surface energy is $(15000 - x)\,\mu$J, find $x$. (Given surface tension = $0.04$ N/m)