List of top Questions asked in JEE Main

Voltage rating of a parallel plate capacitor is $500\,V$. Its dielectric can withstand a maximum electric field of $10^6$ V/m. The plate area is $10^{-4} \; m^2$. What is the dielectric constant is the capacitance is $15\, pF$ ? (given $\in_0 = 8.86 \times 10^{-12} C^2 / Nm^2$)

$Ge$ 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)

With respect to an ore, Ellingham diagram helps to predict the feasibility of its -

The pair that has similar atomic radii is :

A circle touching the x-axis at $(3, 0)$ and making an intercept of length $8$ on the y-axis passes through the point :

A message signal of frequency $100\, MHz$ and peak voltage $100\, V$ is used to execute amplitude modulation on a carrier wave of frequency $300\, GHz$ and peak voltage $400\, V$. The modulation index and difference between the two side band frequencies are :

Sodium metal on dissolution in liquid ammonia gives a deep blue solution due to the formation of:

Water from a tap emerges vertically downwards with an initial speed of $1.0\, ms^{-1}$. The crosssectional area of the tap is $10^{-4} \; m^2$. Assume that the pressure is constant throughout the stream of water and that the flow is streamlined. The cross-sectional area of the stream, $0.15\, m$ below the tap would be : (Take $g \,= \,10\, ms^{-2}$)

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 :

$ {Mn_2(CO)_{10}}$ is an organometallic compound due to the presence of :

A satellite of mass $M$ is in a circular orbit of radius $R$ about the centre of the earth. A meteorite of the same mass, falling towards the earth, collides with the satellite completely inelastically. The speeds of the satellite and the meteorite are the same, just before the collision. The subsequent motion of the combined body will be :

A solution containing $62\, g$ ethylene glycol in $250 \,g$ water is cooled to $-10^{\circ}C$. If $K_f$ for water is $1.86\, K\, kg \,mol^{-1}$, the amount of water (in g) separated as ice is :

What would be the molality of $20\%$ (mass / mass) aqueous solution of $KI$? (molar mass of $KI = 166\, g\, mol^{-1}$)

Haemoglobin and gold sol are examples of :

If a circle of radius $R$ passes through the origin $O$ and intersects the coordinate axes at $A$ and $B$, then the locus of the foot of perpendicular from $O$ on $AB$ is :

If the angle of intersection at a point where the two circles with radii 5 cm and 12 cm intersect is $90^{\circ}$, then the length (in cm) of their common chord is :

If one end of a focal chord of the parabola, $y^2 = 16x$ is at $(1, 4),$ then the length of this focal chord is

If a circle $C$ passing through the point $(4,0)$ touches the circle $x^2 + y^2 + 4x - 6y = 12$ externally at the point $(1, -1)$, then the radius of $C$ is :

The complex that has highest crystal feild splitting energy $(\Delta )$, is :

The pair that does NOT require calcination is:

Hall-Heroult's process is given by :

$C_{60}$, an allotrope of carbon contains :

Iodine reacts with concentrated ${HNO_3}$ to yield $Y$ along with other products. The oxidation state of iodine in $Y$, is :

NaH is an example of :

The compound that inhibits the growth of tumors is :