List of top Physics Questions asked in JEE Main

The photodiode is used to detect the optical signals. These diodes are preferably operated in reverse biased mode because:
If wattless current flows in the AC circuit, then the circuit is:
A curved in a level road has a radius 75 m. The maximum speed of a car turning this curved road can be 30 m/s without skidding. If radius of curved road is changed to 48 m and the coefficient of friction between the tyres and the road remains same, then maximum allowed speed would be ______ m/s.

If K1 and K2 are the thermal conductivities, L1 and L2 are the lengths and A1 and A2 are the cross sectional areas of steel and copper rods respectively such that \(\frac{K_2}{K_1}=9,\frac{A_1}{A_2}=2,\frac{L_1}{L_2}=2.\) 

Then, for the arrangement as shown in the figure, the value of temperature T of the steel-copper junction in the steady state will be

Starting with the same initial conditions, an ideal gas expands from volume V1 to V2 in three different ways. The work done by the gas is W1 if the process is purely isothermal, W2, if the process is purely adiabatic and W3 if the process is purely isobaric. Then, choose the correct option.
The ratio for the speed of the electron in the 3rd orbit of He+ to the speed of the electron in the 3rd orbit of hydrogen atom will be :

Moment of Inertia (M.I.) of four bodies having same mass ‘M‘ and radius ‘2R‘ are as follows:

I1 = M.I. of solid sphere about its diameter

I2 = M.I. of solid cylinder about its axis

I3 = M.I. of solid circular disc about its diameter.

I4 = M.I. of thin circular ring about its diameter

If 2(I2 + I3) + I4 = x⋅ I1 then the value of x will be ______.

Given below are two statements :
Statement I: Davisson-Germer experiment establishes the wave nature of electrons.
Statement II: If electrons have wave nature, they can interfere and show diffraction.
In the light of the above statements choose the correct answer from the option given below :
A set of 20 tuning forks is arranged in a series of increasing frequencies. If each fork gives 4 beats with respect to the preceding fork and the frequency of the last fork is twice the frequency of the first, then the frequency of last fork is _______ Hz
In Bohr’s atomic model of hydrogen, let K, P and E are the kinetic energy, potential energy and total energy of the electron respectively. Choose the correct option when the electron undergoes transitions to a higher level:
A resistor develops 300 J of thermal energy in 15 s, when a current of 2 A is passed through it. If the current increases to 3 A, the energy developed in 10 s is ______ J.
A capacitor is discharging through a resistor R. Consider in time t1, the energy stored in the capacitor reduces to half of its initial value and in time t2, the charge stored reduces to one eighth of its initial value. The ratio t1/t2 will be
A long cylindrical volume contains a uniformly distributed charge of density ρ. The radius of cylindrical volume is R. A charge particle (q) revolves around the cylinder in a circular path. The kinetic energy of the particle is:
The time period of a satellite revolving around earth in a given orbit is 7 hours. If the radius of orbit is increased to three times its previous value, then approximate new time period of the satellite will be
The TV transmission tower at a particular station has a height of 125 m. For doubling the coverage of its range, the height of the tower should be increased by
A \(72\) Ω galvanometer is shunted by a resistance of \(8\) Ω. The percentage of the total current which passes through the galvanometer is
\(\sqrt{d_1}\) and \(\sqrt{d_2}\) are the impact parameters corresponding to scattering angles 60° and 90° respectively, when an α particle is approaching a gold nucleus. For d1 = xd2, the value of x will be ______.
The first overtone frequency of an open organ pipe is equal to the fundamental frequency of a closed organ pipe. If the length of the closed organ pipe is 20 cm. The length of the open organ pipe is ______ cm.
The two light beams having intensities \(I\) and \(9I\) interfere to produce a fringe pattern on a screen. The phase difference between the beams is \(\frac {\pi}{2}\) at point P and \(\pi\) at point Q. Then the difference between the resultant intensities at P and Q will be:
A heat engine operates with the cold reservoir at temperature 324 K. The minimum temperature of the hot reservoir, if the heat engine takes 300 J heat from the hot reservoir and delivers 180 J heat to the cold reservoir per cycle, is _____ K.
A fly wheel is accelerated uniformly from rest and rotates through 5 rad in the first second. The angle rotated by the fly wheel in the next second, will be:
A liquid of density 750 kgm–3 flows smoothly through a horizontal pipe that tapers in cross-sectional area from A1 = 1.2 × 10–2 m2 to \(A_2=\frac{A_1}{2}.\) The pressure difference between the wide and narrow sections of the pipe is 4500 Pa. The rate of flow of liquid is _____ × 10–3 m3s–1.
The total current supplied to the circuit as shown in figure by the 5 V battery is _______ A.
The total current supplied to the circuit
A proton and an alpha particle of the same velocity enter in a uniform magnetic field which is acting perpendicular to their direction of motion. The ratio of the radii of the circular paths described by the alpha particle and proton is
Given below are two statements:
Statement I: In hydrogen atom, the frequency of radiation emitted when an electron jumps from lower energy orbit \((E_1)\) to higher energy orbit \((E_2)\), is given as \(hf = E_1 – E_2.\)
Statement II: The jumping of electron from higher energy orbit \((E_2)\) to lower energy orbit \((E_1)\) is associated with frequency of radiation given as
\(f=\frac{(E_2−E_1)}{h}\) This condition is Bohr’s frequency condition.
In the light of the above statements, choose the correct answer from the options given below: