List of top Questions asked in JCECE

Two capillary of lengths L and 2L and of radii R and 2R are connected in series. The net rate of flow of fluid through them will be (Given rate of the flow through single capillary.$X=\frac{\pi pR^4}{8\eta L})$
Ideal gas and real gas have major difference of
A 16 kg block moving on a frictionless horizontal surface with a velocity of 4 m/s compresses an ideal spring and comes to rest. If the force constant of the spring be 100 N/m, then the spring is compressed by
A parallel plate air capacitor has a capacitance $C$. When it is half filled with a dielectric of dielectric constant $5$, the percentage increase in the capacitance will be :
A free neutron decays spontaneously into
Two cells each of same emf e but of internal resistances $ r_1 $ and $ r_2 $ are connected in series through an external resistance R. If the potential difference between the ends of the first cell is zero, what will be the value of R in terms of $ r_1 $ and $ r_2 $ ?
A sealed container with negligible coefficient of volumetric expansion contains helium (a monoatomic gas). When it is heated from 300 K to 600 K, the average KE of helium atoms is
A choke is preferred to a resistance for limiting current in AC circuit because
The equation of a simple harmonic wave is given by $y=5\, \sin \frac{\pi}{2}(100\, t-x)$, where $x$ and $y$ are in meter and time is in second. The period of the wave in second will be
The twinkling effect of star light is due to
A beam of monochromatic blue light of wavelength $4200\, ?? in air travels in water of refractive index $4/3$. Its wavelength in water will be:
Which one of the following aqueous solutions will exhibit highest boiling point?
The enthalpies of combustion of carbon and carbon monoxide are $ -393.5 $ and $ -283\,\text{kJ}\,\text{mo}{{\text{l}}^{-1}} $ respectively. The enthalpy of formation of carbon monoxide per mol is
What is the equilibrium expression for the reaction, $ {{P}_{4}}(s)+5{{O}_{2}}(g) \rightleftharpoons {{P}_{4}}{{O}_{10}}(s)? $
Which among the following factors is the most important in making fluorine the strongest oxidising agent?
1.520 g of hydroxide of a metal on ignition gave 0.995 g of its oxide. The equivalent weight of the metal is
A ball is thrown from a point with a speed $ {{\text{v}}_{\text{0}}} $ at an angle of projection $ \theta . $ From the same point and at the same instant, a person starts running with a constant speed $ \frac{{{v}_{0}}}{2} $ to catch the ball. Will the person be able to catch the ball? If yes, what should be the angle of projection?
Spherical balls of radius R are falling in a viscous fluid of viscosity $ \eta $ with a velocity v. The retarding viscous force acting on the spherical ball is
In radioactive decay process, the negatively charged emitted (3-particles are
The mass of the earth is $6 \times 10^{24}\, kg$ and that of the moon is $7.4 \times 10^{22}\, kg$. The potential energy of the system is $-7.79 \times 10^{28}\, J$. The mean distance between the earth and moon is $(G = 6.67 \times 10^{-11}\, N\, m^2kg^{-2})$
A particle moves in a straight line with retardation proportional to its displacement. Its loss of kinetic energy for any displacement $ x $ is proportional to
What is the value of inductance L for which the current is a maximum in a series LCR circuit with $ C=10\mu F $ and $ \omega =1000\,{{s}^{-1}} $ ?
Three point charges $ +\,q,-2q $ and $ +q $ are placed at points $ (x=0,y=a,z=0), $ $ (x=0,y=0,z=0) $ and $ (x=a,y=0,z=0), $ respectively. The magnitude and direction of the electric dipole moment vector of this charge assembly are
What is wrong about $CO_3^{2-} \, ion ?$
Consider the acidity of the carboxylic acids (i) PhCOOH (ii) $o-NO_2C_6H_4COOH$ (iii) $p-NO_2C_6H_4COOH$ (iv) $m-NO_2C_6H_4COOH$ Which of the following orders is correct?