List of top Questions asked in JEE Main

Identify A in the given chemical reaction.

Seliwanoff test and Xanthoproteic test are used for the identification of ___________ and ________ respectively.

Match List - I with List - II.

	List - I		List - II
(a)	Sucrose	(i)	\(\beta\)-D-Galactose and \(\beta\)-D-Glucose
(b)	Lactose	(ii)	\(\alpha\)-D-Glucose and \(\beta\)-D-Fructose
(c)	Maltose	(iii)	\(\alpha\)-D-Glucose and \(\alpha\)-D-Glucose

Choose the correct answer from the options given below :

Identify A in the given reaction.

Match List - I with List - II.

Choose the correct answer from the options given below :

Identify A in the following chemical reaction.

2, 4-DNP test can be used to identify :

Which pair of oxides is acidic in nature?

Which of the following forms of hydrogen emits low energy \(\beta^-\) particles?

A. Phenyl methanamine

B. N,N-Dimethylaniline

C. N-Methyl aniline

D. Benzenamine

Choose the correct order of basic nature of the above amines.

Ceric ammonium nitrate and \(\mathrm{CHCl_3}\)/alc. KOH are used for the identification of functional groups present in __________ and _______ respectively.

In \(\overset{1}{\mathrm{C}}\mathrm{H_2} = \overset{2}{\mathrm{C}} = \overset{3}{\mathrm{C}}\mathrm{H} - \overset{4}{\mathrm{C}}\mathrm{H_3}\) molecule, the hybridization of carbon 1, 2, 3 and 4 respectively, are :

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A : In \(\mathrm{TlI_3}\), isomorphous to \(\mathrm{CsI_3}\), the metal is present in +1 oxidation state.

Reason R : Tl metal has fourteen f electrons in its electronic configuration.

In the light of the above statements, choose the most appropriate answer from the options given below :

Match List - I with List - II.

	List - I (Molecule)		List - II (Bond order)
(a)	\(\mathrm{Ne_2}\)	(i)	1
(b)	\(\mathrm{N_2}\)	(ii)	2
(c)	\(\mathrm{F_2}\)	(iii)	0
(d)	\(\mathrm{O_2}\)	(iv)	3

Choose the correct answer from the options given below :

A point source of light S, placed at a distance 60cm in front of the centre of a plane mirror of width 50 cm, hangs vertically on a wall. A man walks in front of the mirror along a line parallel to the mirror at a distance 1.2 m from it (see in the figure). The distance between the extreme points where he can see the image of the light source in the mirror is __________ cm.

If the highest frequency modulating a carrier is 5 kHz, then the number of AM broadcast stations accommodated in a 90 kHz bandwidth are _________.

The zener diode has a \(V_z = 30\ \mathrm{V}\). The current passing through the diode for the following circuit is ________ mA.

Time period of a simple pendulum is \(T\). The time taken to complete \(\frac{5}{8}\) oscillations starting from mean position is \(\frac{\alpha}{\beta}T\). The value of \(\alpha\) is _________.

The volume \(V\) of a given mass of monoatomic gas changes with temperature \(T\) according to the relation \(V = KT^{\frac{2}{3}}\). The workdone when temperature changes by 90K will be \(xR\). The value of \(x\) is _________. [R = universal gas constant]

In the reported figure of earth, the value of acceleration due to gravity is same at point A and C but it is smaller than that of its value at point B (surface of the earth). The value of OA : AB will be x : y. The value of x is ________.

A cord is wound round the circumference of wheel of radius r. The axis of the wheel is horizontal and the moment of inertia about it is I. A weight mg is attached to the cord at the end. The weight falls from rest. After falling through a distance 'h', the square of angular velocity of wheel will be :

A particle executes S.H.M., the graph of velocity as a function of displacement is :

A particle executes S.H.M. with amplitude 'a', and time period 'T'. The displacement of the particle when its speed is half of maximum speed is \(\frac{\sqrt{x}\,a}{2}\). The value of \(x\) is __________.

A tuning fork A of unknown frequency produces 5 beats/s with a fork of known frequency 340 Hz. When fork A is filed, the beat frequency decreases to 2 beats/s. What is the frequency of fork A?

A radioactive sample is undergoing \(\alpha\) decay. At any time \(t_1\), its activity is \(A\) and another time \(t_2\), the activity is \(\frac{A}{5}\). What is the average life time for the sample?