List of top Physics Questions asked in JEE Main

An AC source is connected to an inductance of 100 mH, a capacitance of 100 μF and a resistance of 120 Ω as shown in the figure. The time in which the resistance having a thermal capacity 2 J/°C will get heated by 16°C is ___ s.
 

Fig. Circuit

A telegraph line of length 100km has a capacity of 0.01μF/km, and it carries an alternating current at 0.5kilo cycle per second. If the minimum impedance is required, then the value of the inductance that needs to be introduced in series is ______ mH.
(if π = √10)

The intensity of the light from a bulb incident on a surface is 0.22 W/m2. The amplitude of the magnetic field in this light-wave is ___ × 10–9 T.

(Given : Permittivity of vacuum ε0 = 8.85 × 10–12C2N–1–m–2, speed of light in vacuum c = 3 × 108 ms–1)

As per the given figure, two plates A and B of thermal conductivity K and 2 K are joined together to form a compound plate. The thickness of plates are 4.0 cm and 2.5 cm, respectively and the area of cross-section is 120 cm2 for each plate. The equivalent thermal conductivity of the compound plate is \((1+\frac{5}{α})K,\) then the value of α will be ___.

As per the given figure, two plates A and B of thermal conductivity K and 2 K are joined together to form a compound plate

Two travelling waves of equal amplitudes and equal frequencies move in opposite directions along a string. They interfere to produce a stationary wave whose equation is given by \(y = (10 cos \ \pi x\ sin \frac {2\pi t}{T})\) cm. The amplitude of the particle at \(x = \frac 43\) cm will be _______ cm.
In an experiment to verify Newton’s law of cooling, a graph is plotted between, the temperature difference (ΔT) of the water and surroundings and time as shown in figure. The initial temperature of water is taken as 80ºC. The value of \(t_2\) as mentioned in the graph will be ______.
graph is plotted between, the temperature difference (ΔT) of the water and surroundings and time

A pendulum is suspended by a string of length 250 cm. The mass of the bob of the pendulum is 200 g. The bob is pulled aside until the string is at 60° with vertical, as shown in the figure. After releasing the bob, the maximum velocity attained by the bob will be ___ ms–1. (if g = 10 m/s2)
 

Fig. Oscillations
A circular coil of \(1000\) turns each with area \(1\ m^2\) is rotated about its vertical diameter at the rate of one revolution per second in a uniform horizontal magnetic field of \(0.07\ T\). The maximum voltage generation will be _____ V.
A man of 60 kg is running on the road and suddenly jumps into a stationary trolly car of mass 120 kg. Then, the trolly car starts moving with velocity 2ms–1. The velocity of the running man was _____ ms–1, when he jumps into the car.
In the given circuit, the value of current \(I_L\) will be __________ mA. (When \(R_L = 1\ kΩ\))
In the given circuit, the value of current IL
A monoatomic gas performs a work of \(\frac Q4\) where \(Q\) is the heat supplied to it. The molar heat capacity of the gas will be ____ \(R\) during this transformation. Where \(R\) is the gas constant.
In the hydrogen spectrum, λ be the wavelength of first transition line of Lyman series. The wavelength difference will be “aλ” between the wavelength of 3rd transition line of the Paschen series and that of 2nd transition line of Balmer series where a = ______.
The oscillating magnetic field in a plane electromagnetic wave is given by By = \(5 × 10^{–6}\) \(sin\;1000\;π(5x – 4 × 108\;t)T\). The amplitude of electric field will be:
A wire of length L and radius r is clamped rigidly at one end. When the other end of the wire is pulled by a force F, its length increases by 5 cm. Another wire of the same material of length 4L and radius 4r is pulled by a force 4F under same conditions. The increase in length of this wire is ___ cm.
A condenser of 2μF capacitance is charged steadily from 0 to 5 C.Which of the following graph represents correctly the variation of potential difference (V) across it’s plates with respect to the charge (Q) on the condenser?
A unit scale is to be prepared whose length does not change with temperature and remains 20 cm, using a bimetallic strip made of brass and iron each of different length. The length of both components would change in such a way that difference between their lengths remains constant. If length of brass is 40 cm and length of iron will be ___ cm.
In the given figure, the value of V0 will be ______ V.
the value of V0 will be
The magnetic moment of an electron (e) revolving in an orbit around nucleus with an orbital angular momentum is given by:
The rms value of the conduction current in a parallel plate capacitor is 6.9 μA. The capacity of this capacitor, if it is connected to 230 V ac supply with an angular frequency of 600 rad/s, will be :
Only 2% of the optical source frequency is the available channel bandwidth for an optical communicating system operating at 1000 nm. If an audio signal requires a bandwidth of 8 kHz, how many channels can be accommodated for transmission?
A parallel plate capacitor filled with a medium of dielectric constant 10, is connected across a battery and is charged. The dielectric slab is replaced by another slab of dielectric constant 15. Then the energy of capacitor will 
For forces are acting at a point P in equilibrium as shown in the figure. The ratio of force F1 to F2 is 1 : x where x =___.
forces are acting at a point P in equilibrium
The volume charge density of a sphere of radius 6 m is 2μC cm-3. The number of lines of force per unit surface area coming out from the surface of the sphere is _______ × 1010 NC-1.

In the circuit, the logical value of A = 1 or B = 1 when potential at A or B is 5 V and the logical value of A = 0 or B = 0 when potential at A or B is 0 V. The truth table of the given circuit will be:

 

A ball of mass \(0.15\) \(kg\) hits the wall with its initial speed of \(12\) \(ms^{–1}\) and bounces back without changing its initial speed. If the force applied by the wall on the ball during the contact is \(100\) \(N\), calculate the time duration of the contact of ball with the wall.