List of top Questions asked in JEE Main- 2020

If the number of integral terms in the expansion of \((3^{1/2} + 5^{1/8})^n\) is exactly 33, then the least value of \(n\) is :

For the frequency distribution :
Variate (x) : \(x_1\) \(x_2\) \(x_3\) .... \(x_{15}\)
Frequency (f) : \(f_1\) \(f_2\) \(f_3\) ...... \(f_{15}\)
where \(0 \lt x_1 \lt x_2 \lt x_3 \lt ... \lt x_{15} = 10\) and \(\sum_{i=1}^{15} f_i \gt 0\), the standard deviation cannot be :

The function, \(f(x) = (3x - 7)x^{2/3}\), \(x \in \mathbb{R}\), is increasing for all \(x\) lying in :

The area (in sq. units) of the region \(\{(x, y) : 0 \le y \le x^2 + 1,\ 0 \le y \le x + 1,\ \frac{1}{2} \le x \le 2\}\) is :

Two elements A and B have similar chemical properties. They don’t form solid hydrogencarbonates, but react with nitrogen to form nitrides. A and B, respectively, are :

The ratio of the mass percentages of ‘C & H’ and ‘C & O’ of a saturated acyclic organic compound ‘X’ are 4 : 1 and 3 : 4 respectively. Then, the moles of oxygen gas required for complete combustion of two moles of organic compound ‘X’ is ________.

For the disproportionation reaction
\(\mathrm{2Cu^+(aq) \rightleftharpoons Cu(s) + Cu^{2+}(aq)}\) at 298 K. \(\ln K\) (where K is the equilibrium constant) is ___________ \(\times 10^{-1}\).
Given : ( \(E^0_{\mathrm{Cu^{2+}/Cu^+}} = 0.16\) V, \(E^0_{\mathrm{Cu^+/Cu}} = 0.52\) V, \(\dfrac{RT}{F} = 0.025\) )

The work function of sodium metal is \(4.41 \times 10^{-19}\) J. If photons of wavelength 300 nm are incident on the metal, the kinetic energy of the ejected electrons will be (h = \(6.63 \times 10^{-34}\) J s; c = \(3 \times 10^{8}\) m/s) ________ \(\times 10^{-21}\) J.

Amongst the following statements regarding adsorption, those that are valid are

(a) \(\Delta H\) becomes less negative as adsorption proceeds
(b) On a given adsorbent, ammonia is adsorbed more than nitrogen gas
(c) On adsorption, the residual force acting along the surface of the adsorbent increases
(d) With increase in temperature, the equilibrium concentration of adsorbate increases

The molecular geometry of \(\mathrm{SF_6}\) is octahedral. What is the geometry of \(\mathrm{SF_4}\) (including lone pair(s) of electrons, if any)?

Three elements X, Y and Z are in the 3^rd period of the periodic table. The oxides of X, Y and Z, respectively, are basic, amphoteric and acidic. The correct order of the atomic numbers of X, Y and Z is :

If you spill a chemical toilet cleaning liquid on your hand, your first aid would be

The results given in the below table were obtained during kinetic studies of the following reaction
\(2A + B \to C + D\)

Experiment	[A]/mol L-1	[B]/mol L-1	Initial rate/mol L-1 min-1
I	0.1	0.1	\(6.00 \times 10^{-3}\)
II	0.1	0.2	\(2.40 \times 10^{-2}\)
III	0.2	0.1	\(1.20 \times 10^{-2}\)
IV	X	0.2	\(7.20 \times 10^{-2}\)
V	0.3	Y	\(2.88 \times 10^{-1}\)

X and Y in the given table are respectively :

The size of a raw mango shrinks to a much smaller size when kept in a concentrated salt solution. Which one of the following processes can explain this?

Match the type of interaction in column A with the distance dependence of their interaction energy in column B

A	B
(i) ion-ion	(a) \(\frac{1}{r}\)
(ii) dipole-dipole	(b) \(\frac{1}{r^2}\)
(iii) London dispersion	(c) \(\frac{1}{r^3}\)
	(d) \(\frac{1}{r^6}\)

The number of subshells associated with \(n = 4\) and \(m = -2\) quantum numbers is

The one that is not expected to show isomerism is :

A light ray enters a solid glass sphere of refractive index \(\mu = \sqrt{3}\) at an angle of incidence \(60^\circ\). The ray is both reflected and refracted at the farther surface of the sphere. The angle (in degrees) between the reflected and refracted rays at this surface is ________.

A heat engine is involved with exchange of heat of 1915 J, \(-40\) J, \(+125\) J and \(-Q\) J, during one cycle achieving an efficiency of 50.0%. The value of \(Q\) is

In a hydrogen atom the electron makes a transition from \((n+1)^{th}\) level to the \(n^{th}\) level. If \(n \gg 1\), the frequency of radiation emitted is proportional to :

An inductance coil has a reactance of 100 \(\Omega\). When an AC signal of frequency 1000 Hz is applied to the coil, the applied voltage leads the current by 45^o. The self-inductance of the coil is

A capillary tube made of glass of radius 0.15 mm is dipped vertically in a beaker filled with methylene iodide (surface tension = 0.05 Nm^-1, density = 667 kg m^-3) which rises to height \(h\) in the tube. It is observed that the two tangents drawn from liquid-glass interfaces (from opp. sides of the capillary) make an angle of 60^o with one another. Then \(h\) is close to (\(g = 10\ \mathrm{ms^{-2}}\))

In a Young's double slit experiment, 16 fringes are observed in a certain segment of the screen when light of a wavelength 700 nm is used. If the wavelength of light is changed to 400 nm, the number of fringes observed in the same segment of the screen would be

When the temperature of a metal wire is increased from \(0^{\circ}\mathrm{C}\) to \(10^{\circ}\mathrm{C}\), its length increases by \(0.02\%\). The percentage change in its mass density will be closest to :

A \(10\ \mu\mathrm{F}\) capacitor is fully charged to a potential difference of 50 V. After removing the source voltage it is connected to an uncharged capacitor in parallel. Now the potential difference across them becomes 20 V. The capacitance of the second capacitor is :