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questions
List of practice Questions
Which of the following compound is added to the sodium extract before addition of silver nitrate for testing of halogens?
JEE Main - 2021
JEE Main
Chemistry
Qualitative Analysis
Which one of the following statements is FALSE for hydrophilic sols?
JEE Main - 2021
JEE Main
Chemistry
Surface Chemistry
The correct order of bond dissociation enthalpy is:
JEE Main - 2021
JEE Main
Chemistry
Periodicity of Elements
The method used for the purification of Indium is:
JEE Main - 2021
JEE Main
Chemistry
General Principles and Processes of Isolation of Elements
Water does not produce CO on reacting with:
JEE Main - 2021
JEE Main
Chemistry
Some basic concepts of chemistry
Given below are two statements:
Statement I: $\alpha$ and $\beta$ forms of sulphur can change reversibly between themselves with slow heating or slow cooling.
Statement II: At room temperature the stable crystalline form of sulphur is monoclinic sulphur.
JEE Main - 2021
JEE Main
Chemistry
Periodicity of Elements
The set of elements that are used in the fabrication of transistors is:
JEE Main - 2021
JEE Main
Chemistry
Semiconductor electronics: materials, devices and simple circuits
The wavelength of an X-ray beam is 10 Å. The mass of a fictitious particle having the same energy as that of the X-ray photons is $\frac{x}{3}h$ kg. The value of x is ________ . (h=Planck's constant)
JEE Main - 2021
JEE Main
Physics
Dual nature of radiation and matter
The solubility of Ca(OH)$_2$ in water is:
[Given: The solubility product of Ca(OH)$_2$ in water = 5.5 $\times$ 10⁻⁶]
JEE Main - 2021
JEE Main
Chemistry
Equilibrium
The stopping potential for electrons emitted from a photosensitive surface illuminated by light of wavelength 491 nm is 0.710 V. When the incident wavelength is changed to a new value, the stopping potential is 1.43 V. The new wavelength is:
JEE Main - 2021
JEE Main
Physics
Dual nature of radiation and matter
An electron of mass $m_e$ and a proton of mass $m_p = 1836 m_e$ are moving with the same speed. The ratio of their de Broglie wavelength $\frac{\lambda_{electron}}{\lambda_{proton}}$ will be:
JEE Main - 2021
JEE Main
Physics
Dual nature of radiation and matter
The wavelength of the photon emitted by a hydrogen atom when an electron makes a transition from n=2 to n=1 state is:
JEE Main - 2021
JEE Main
Physics
Atoms
If a message signal of frequency '$f_m$' is amplitude modulated with a carrier signal of frequency '$f_c$' and radiated through an antenna, the wavelength of the corresponding signal in air is:
JEE Main - 2021
JEE Main
Physics
communication systems
Given below are two statements:
Statement I: In a diatomic molecule, the rotational energy at a given temperature obeys Maxwell's distribution.
Statement II: In a diatomic molecule, the rotational energy at a given temperature equals the translational kinetic energy for each molecule.
JEE Main - 2021
JEE Main
Physics
The Kinetic Theory of Gases
An electron with kinetic energy $K_1$ enters between parallel plates of a capacitor at an angle '$\alpha$' with the plates. It leaves the plates at angle '$\beta$' with kinetic energy $K_2$. Then the ratio of kinetic energies $K_1 : K_2$ will be:
JEE Main - 2021
JEE Main
Physics
Electric Field
In a ferromagnetic material, below the curie temperature, a domain is defined as:
JEE Main - 2021
JEE Main
Physics
Magnetism and matter
If the line \( y = mx \) bisects the area enclosed by the lines \( x = 0, y = 0, x = \frac{3}{2} \) and the curve \( y = 1 + 4x - x^2 \), then 12 m is equal to _________.
JEE Main - 2021
JEE Main
Mathematics
Calculus
Let B be the centre of the circle \( x^2 + y^2 - 2x + 4y + 1 = 0 \). Let the tangents at two points P and Q on the circle intersect at the point \( A(3, 1) \). Then \( 8 \cdot \frac{\text{area } \Delta APQ}{\text{area } \Delta BPQ} \) is equal to _________.
JEE Main - 2021
JEE Main
Mathematics
Circles
Suppose the line $\frac{x - 2}{\alpha} = \frac{y - 2}{-5} = \frac{z + 2}{2}$ lies on the plane $x + 3y - 2z + \beta = 0$. Then $(\alpha + \beta)$ is equal to _________.
JEE Main - 2021
JEE Main
Mathematics
3D Geometry
If e is the electronic charge, c is the speed of light in free space and h is Planck's constant, the quantity $\frac{1}{4\pi\epsilon_0}\frac{e^2}{hc}$ has dimensions of:
JEE Main - 2021
JEE Main
Physics
Dimensional Analysis
A stone is dropped from the top of a building. When it crosses a point 5 m below the top, another stone starts to fall from a point 25 m below the top. Both stones reach the bottom simultaneously. The height of the building is:
JEE Main - 2021
JEE Main
Physics
Kinematics
Negation of the statement \((p \lor r) \implies (q \lor r)\) is :
JEE Main - 2021
JEE Main
Mathematics
mathematical reasoning
If \( S = \frac{7}{5} + \frac{9}{5^2} + \frac{13}{5^3} + \frac{19}{5^4} + ... \), then 160 S is equal to _________.
JEE Main - 2021
JEE Main
Mathematics
Sequence and series
Let \( f(x) \) be a cubic polynomial with \( f(1) = -10 \), \( f(-1) = 6 \), and has a local minima at \( x = 1 \), and \( f'(x) \) has a local minima at \( x = -1 \). Then \( f(3) \) is equal to _________.
JEE Main - 2021
JEE Main
Mathematics
Application of derivatives
If \( \int \frac{\sin x}{\sin^3 x + \cos^3 x} dx = \alpha \log_e |1 + \tan x| + \beta \log_e |1 - \tan x + \tan^2 x| + \gamma \tan^{-1} \left( \frac{2 \tan x - 1}{\sqrt{3}} \right) + C \), when C is a constant of integration, then the value of \( 18(\alpha + \beta + \gamma^2) \) is _________.
JEE Main - 2021
JEE Main
Mathematics
Calculus
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