List of top Questions asked in JEE Main- 2019

Figure shown a $DC$ voltage regulator circuit, with a Zener diode of breakdown voltage = $6V$. If the unregulated input voltage varies between $10\, V$ to $16\, V$, then what is the maximum Zener current ?

Find the magnetic field at point $P$ due to a straight line segment $AB$ of length $6\, cm$ carrying a current of $5\, A$. (See figure) ($\mu_0 \, = \, 4\pi \times \, 10^{-7} \, N-A^{-2})$

For a reaction, $N_2(g) + 3H_2(g) \rightarrow 2NH_3(g)$; identify dihydrogen $(H_2)$ as a limiting reagent in the following reaction mixtures.

For a uniformly charged ring of radius $R$, the electric field on its axis has the largest magnitude at a distance $h$ from its centre. Then value of $h$ is :

For coagulation of arscnious sulphide sol, which one of the following salt solution will be most effective ?

For emission line of atomic hydrogen from $n_i = 8$ to $n_f $ = the plot of wave number $(\bar{v})$ against $( \frac{1}{n^2})$ will be (The Ry dberg constant, $R_H$ is in wave number unit).

For the circuit shown below, the current through the Zener diode is :

For the following reactions, equilibrium constants are given : $S\left(s\right)+O_{2}\left(g\right) $${\rightleftharpoons}$$SO_{2}\left(g\right); K_{1} =10^{52}$ $2S\left(s\right)+3O_{2}\left(g\right) $${\rightleftharpoons}$$2SO_{3}\left(g\right); K_{2} = 10^{129}$ The eqilibrium constant for the reaction, $2SO_{2}\left(g\right)+O_{2}\left(g\right)$${\rightleftharpoons}$$2SO_{3}\left(g\right)$ is :

For the given cyclic process $CAB$ as shown for a gas, the work done is :

For the reaction, ${2A + B \to }$ products, when the concentrations of A and B both where doubled , the rate of the reaction increased from $0.3 \; mol \; L^{-1} s^{-1 }$ to $2.4 \; mol \; L^{-1} s^{-1}$. When the concentration of A alone is doubled, the rate increased from $0.3 \; mol \; L^{-1} s^{-1}$ to $0.6 \; mol \; L^{-1} s^{-1}$ Which one of the following statements is correct ?

For $x > 1$, if $(2x)^{2y} = 4e^{2x - 2y}$, then $\left( 1 +\log_{e} 2x\right)^{2} \frac{dy}{dx} $ is equal to :

Four identical particles of mass $M$ are located at the corners of a square of side $'a'$. What should be their speed if each of them revolves under the influence of other?s gravitational field in a circular orbit circumscribing the square?

Freezing point of a $4\%$ aqueous solution of $X$ is equal to freezing point of $12\%$ aqueous solution of $Y$. If molecular weight of $X$ is $A$, then molecular weight of $Y$ is :

Fructose and glucose can be distinguished by :

$Ge$ and $Si$ diodes start conducting at $0.3 \,V$ and $0.7\, V$ respectively. In the following figure if Ge diode connection are reversed, the value of $V_o$ changes by : (assume that the Ge diode has large breakdown voltage)

Given $\frac{b+c}{11} = \frac{c+a}{12}= \frac{a+b}{13} $ for a $ \Delta ABC$ with usual notation. If $ \frac{\cos A}{\alpha} = \frac{\cos B}{\beta} = \frac{\cos C}{\gamma} $ , then the ordered triad $( \alpha, \beta, \gamma)$ has a value :

Haemoglobin and gold sol are examples of :

Half mole of an ideal monoatomic gas is heated at constant pressure of 1 atm from $20{^{\circ}C}$ to $90^{\circ}C$. Work done by gas is close to : ( Gas constant R = $8.31\, J\, /mol-K$)

Hall-Heroult's process is given by :

Heat treatment of muscular pain involves radiation of wavelength of about $900\, nm$. Which spectral line of H-atom is suitable for this purpose ? $[R_H = 1 \times 10^5 \; cm^{-1}, h = 6.6 \times 10^{-34} \; Js, c = 3 \times 10^8 \; ms^{-1}]$

Hinsberg's reagent is :

Homoleptic octahedral complexes of a metal ion '${M^{3+} }$' with three monodentate ligands and $L_1, L_2, L_3$ absorb wavelengths in the region of green, blue and red respectively. The increasing order of the ligand strength is :

Ice at $-20^{\circ} C$ os added tp $50\, g$ of water at $40^{\circ}C$. When the temperature of the mixture reaches $0^{\circ}C$, it is found that $20\, g$ of ice is still unmelted. The amount of ice added to the water was close to (Specific heat of water = $4.2 \; J/g/^{\circ}C$) Specific heat of Ice = $2.1 \; J/g/^{\circ}C$ Heat of fusion of water at $0^{\circ}C = 334 \; J/g$)

If $\begin {bmatrix} 1 & 1 \\ 0 & 1 \end {bmatrix}$ . $\begin {bmatrix} 1 & 2 \\ 0 & 1 \end {bmatrix} $ . $\begin {bmatrix} 1 & 3 \\ 0 & 1 \end {bmatrix}$ ..... $\begin {bmatrix} 1 & n-1 \\ 1 & 1 \end {bmatrix}$ = $\begin {bmatrix} 1 & 78 \\ 0 & 1 \end {bmatrix}$, then the inverse of $\begin {bmatrix} 1 & n \\ 0 & 1 \end {bmatrix}$ is

If $10^{22}$ gas molecules each of mass $10^{-26}$ kg collide with a surface (perpendicular to it) elastically per second over an area $1\, m^2$ with a speed $10^4$ m/s, the pressure exerted by the gas molecules will be of the order of :