List of top Questions asked in JEE Main

Which transition in the hydrogen spectrum would have the same wavelength as the Balmer type transition from $n =4$ to $n =2$ of $He ^{+}$spectrum

The temperature of an ideal gas is increased from 200 K to 800 K. If r.m.s. speed of gas at 200K is v0. Then, r.m.s. speed of the gas at 800 K will be

Let A= {–4, –3, –2, 0, 1, 3, 4} and R = {(a, b) ∈ A × A : b = |a| or b² = a + 1} be a relation on A. Then the minimum number of elements, that must be added to the relation R so that it becomes reflexive and symmetric, is_____.

The temperature of the body drops from 60°C to 40°C in 7 min. The surrounding temperature is 10°C. The temperature of the body drops from 40°C to T°C in 7 min. Find the value of T

Let $ (\alpha, \beta) $ be the centroid of the triangle formed by the lines $ 15x - y = 82 $, $ 6x - 5y = -4 $, and $ 9x + 4y = 17 $. Then $ \alpha + 2\beta $ and $ 2\alpha - \beta $ are the roots of the equation:

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: When you squeeze one end of a tube to get toothpaste out from the other end, Pascal's principle is observed.
Reason R: A change in the pressure applied to an enclosed incompressible fluid is transmitted undiminished to every portion of the fluid and to the walls of its container.
In the light of the above statements, choose the most appropriate answer from the options given below:

All words, with or without meaning, are made using all the letters of the word MONDAY. These words are written as in a dictionary with serial numbers. The serial number of the word MONDAY is

Choose the incorrect statement from the given statements.

Let N be the foot of perpendicular from the point P (1, –2, 3) on the line passing through the points (4, 5, 8) and (1, –7, 5). Then the distance of N from the plane 2x – 2y + z + 5 = 0 is

Let the centre of a circle C be (α, β) and its radius r < 8. Let 3x + 4y = 24 and 3x – 4y = 32 be two tangents and 4x + 3y =1 be a normal to C. Then (α – β + r) is equal to

A child of mass 5 kg is going round a merry-goround that makes 1 rotation in 3.14 s. The radius of the merry-go-round is 2 m. The centrifugal force on the child will be

Identify $X , Y$ and $Z$ in the following reaction (Equation not balanced) $ClO + NO _2 \rightarrow \underline{ X } \stackrel{ H _2 O }{\longrightarrow} \underline{ Y }+\underline{Z}$

The random valuable X follows binomial distribution B (n, p) for which the difference of the mean and the variance is 1. If 2P(X = 2) = 3P(X = 1), then n²P(X > 1) is equal to

Which one of the following statements is correct for electrolysis of brine solution?

The value of $\frac{e^{-\frac{\pi}{4}}+\int^{\frac{\pi}{4}}_{0}e^{-x}\tan^{50}x\ dx}{\int^{\frac{\pi}{4}}_{0}e^{-x}(\tan^{49}x+\tan^{51}x)dx}$ is

As shown in the figure, a particle is moving with constant speed π m/s. Considering its motion from A to B, the magnitude of the average velocity is

Let$ |\vec{a}|=2, |\vec{b}|=3$ and the angle between the vectors $\vec{a}$ and $\vec{b}$ be $\frac{π}{4}$. Then $|(\vec{a}+2\vec{b})×(2\vec{a}-3\vec{b})|^2$ is equal to

A protein ' $X$ ' with molecular weight of $70,000 u$, on hydrolysis gives amino acids One of these amino acid is

A 2 meter long scale with least count of 0.2 cm is used to measure the locations of objects on an optical bench. While measuring the focal length of a convex lens, the object pin and the convex lens are placed at 80 cm mark and lm mark, respectively. The image of the object pin on the other side of lens coincides with image pin that is kept at 180 cm mark. The % error in the estimation of focal length is

Let $S=\left\{z∈C : \bar{z}=i(z^2+Re(\bar{z}))\right\}$. Then $\sum\limits_{z∈S}|z|^2$ is equal to

The statement (p∧ (-q)) v ((~ p) ∧ q) v ((~q)) is equivalent to

If the system of equations
2x + y - z = 5
2x -5y + λz = μ
x + 2y - 5z = 7
has infinitely many solutions, then (λ + μ)² + (λ - μ)²is equal to

Let a₁, a₂, a₃, …. be a G.P. of increasing positive numbers. Let the sum of its 6^th and 8^th terms be 2 and the product of its 3rd and 5th terms be $\frac{1}{9}$ .Then 6 (a₂ + a₄) (a₄ + a₆) is equal to

The methods NOT involved in concentration of ore are
A Liquation
B Leaching
C Electrolysis
D Hydraulic washing
E Froth floatation
Choose the correct answer from the options given below :

Which of the following artificial sweeteners has the highest sweetness value in comparison to cane sugar?