JEE Main entrance exam Question Bank Solutions for Physics (JEE Main)

When ₃Li⁷ nuclei are bombarded by protons, and the resultant nuclei are ₄Be⁸, the emitted particles will be ______.

In the nuclear fusion reaction

\[\ce{^2_1H + ^3_1H-> ^4_2He + n}\]

given that the repulsive potential energy between the two nuclei is ∼ 7.7 × 10^-14J, the temperature at which the gases must be heated to initiate the reaction is nearly

[Boltzmann's Constant k = 1.38 × 10^-23 J/K]

Two identical beakers A and B contain equal volumes of two different liquids at 60°C each and is left to cool down. Liquid in A has a density of 8 × 10² kg/m³ and specific heat of 2000 J kg^-1 K^-1 while the liquid in B has a density of 10³ kg m^-3 and specific heat of 4000 J kg^-1 K^-1. Which of the following best describes their temperature versus time graph schematically? (assume the emissivity of both the beakers to be the same.)

Consider a finite insulated, uncharged conductor placed near a finite positively charged conductor. The uncharged body must have a potential:

An earthen pitcher loses 1 gm of water per minute due to evaporation. If the water equivalent of the pitcher is 0.5 kg and the pitcher contains 9.5 kg of water, calculate the time required for the water in a pitcher to cool to 28°C from the original temperature of 30°C. Neglect radiation effects. The latent heat of vaporization in this range of temperature is 580 Cal/gm and the specific heat of water is 1 Cal/gm°C.

Heat given to a body that raises its temperature by 1°C is ______.

The displacement current of 4.425 µA is developed in the space between the plates of the parallel plate capacitor when voltage is changing at a rate of 10⁶ Vs^-1. The area of each plate of the capacitor is 40 cm². The distance between each plate of the capacitor is x × 10^-3 m. The value of x is ______.

(Permittivity of free space, ε₀ = 8.85 × 10^-12C²N^-1m^-2).

For changing the capacitance of a given parallel plate capacitor, a dielectric material of dielectric constant K is used, which has the same area as the plates of the capacitor.

The thickness of the dielectric slab is `3/4`d, where 'd' is the separation between the plate of the parallel plate capacitor.

The new capacitance (C') in terms of the original capacitance (C₀) is given by the following relation:

The material filled between the plates of a parallel plate capacitor has a resistivity of 200Ωm. The value of the capacitance of the capacitor is 2 pF. If a potential difference of 40V is applied across the plates of the capacitor, then the value of leakage current flowing out of the capacitor is ______.

(given the value of relative permittivity of a material is 50.)

A 5µF capacitor is charged fully by a 220 V supply. It is then disconnected from the supply and is connected in series to another uncharged 2.5 µF capacitor If the energy change during the charge redistribution is `"X"/100`J then value of X to the 100 nearest integer is ______.

Two plates A and B of a parallel plate capacitor are arranged in such a way, that the area of each plate is S = 5 × 10^-3 m 2 and distance between them is d = 8.85 mm. Plate A has a positive charge q₁ = 10^-10 C and Plate B has charge q₂ = + 2 × 10^-10 C. Then the charge induced on the plate B due to the plate A be - (....... × 10^-11 )C

A leaky parallel plate capacitor is filled completely with a material having dielectric constant K = 5 and electric conductivity σ = 7.4 × 10^-12 Ω^-1 m^-1. If the charge on the plate at the instant t = 0 is q = 8.85 µC, then the leakage current at the instant t = 12 s is ______ × 10^-1 µA.

A capacitor of capacity 2 µF is charged to a potential difference of 12 V. It is then connected across an inductor of inductance 0.6 mH. The current in the circuit at a time when the potential difference across the capacitor is 6.0 V is ______ × 10^-1A.

A capacitor has charge 50 µC. When the gap between the plate is filled with glass wool, then 120 µC charge flows through the battery to capacitor. The dielectric constant of glass wool is ______.

Current versus time and voltage versus time graphs of a circuit element are shown in figure.

The type of the circuit element is ______.

Two identical capacitors are connected as shown and have an initial charge of Q₀. The separation between the plates of each capacitor is d₀. Suddenly the left plate of the upper capacitor and right plate of the lower capacitor start moving with speed v towards the left while the other plate of each capacitor remains fixed. `("given" (Q_0V)/(2d_0) = 10 A)`. The value of current in the circuit is ______ A.

A capacitor with capacitance 5µF is charged to 5 µC. If the plates are pulled apart to reduce the capacitance to 2 µF, how much work is done?

At what temperature a gold ring of diameter 6.230 cm be heated so that it can be fitted on a wooden bangle of diameter 6.241 cm? Both diameters have been measured at room temperature (27°C). (Given: coefficient of linear thermal expansion of gold α_L = 1.4 × 10^-5 K^-1).

Each side of a box made of metal sheet in cubic shape is 'a' at room temperature 'T', the coefficient of linear expansion of the metal sheet is 'α'. The metal sheet is heated uniformly, by a small temperature ΔT, so that its new temeprature is T + ΔT. Calculate the increase in the volume of the metal box.

If the length of a cylinder on heating increases by 2%, the area of its base will increase by ______.