List of top Questions asked in JCECE

In the figure, the ball P is released from rest, when the spring is at its natural length. For the block Q of mass $ 2{{m}_{0}} $ to leave contact with ground at some stage, the minimum mass of P must be

A $ 50\,\Omega $ galvanometer is shunted by a resistance of $ 5\,\Omega . $ The percentage of the total current, which passes through the galvanometer is

The effective resistance across the points P and Q is

A disc of radius a and mass m is pivoted at the rim and is set in small oscillation. If a simple pendulum have the same period as that of the disc, then the length of the simple pendulum should be

An elliptically shaped ring of dimensions shown in figure just touches, the horizontal surface of a liquid of surface tension S. The force required to pull the ring away from the liquid surface is

A physical quantity X is represented by $ X=[{{M}^{\eta }}{{L}^{-\theta }}{{T}^{-\text{o }\!\!|\!\!\text{ }}}]. $ The maximum percentage errors in the measurement of M, L and T, respectively are $ \alpha %,\beta % $ and $ \gamma %. $ The maximum percentage error in the measurement of X will be

An artificial satellite moving in a circular orbit around the earth has a total (kinetic + potential) energy $ \frac{{{E}_{0}}}{4}. $ Its potential energy is

A plano-convex glass lens $ ({{\mu }_{g}}=3/2) $ of radius of curvature $ R=20\text{ }cm $ is placed at a distance a from a concave lens of focal length 40 cm. What should be the distance b of a point object O from plano-convex lens so that the position of final image is independent of a?

A hollow conducting sphere is placed in an electric field produced by a point charg placed at $P$ as shown in figure. Let $V_A, V_B, V_C$ be the potentials at points $A, B$ and $C$ respectively. Then

$A\, 2\,V$ battery, a $15\, \Omega$ resistor and a potentiometer of $100\, cm$ length, all are connected in series. If the resistance of potentiometer wire is $5\, \Omega$ , then the potential gradient of the potentiometer wire is

An open pipe of length 33 cm resonates with frequency of 1000 Hz. If the speed of sound is $ 333\,m{{s}^{-1}}, $ then this frequency is

Two pendulum have time period T and $ \frac{5T}{4} $ they start SHM at the same time form the mean position. What will be the phase difference between them after the bigger pendulum completed one oscillation

A ball rolls of the top of a stair way with a horizontal velocity $ u\,m{{s}^{-1}}. $ If the steps are $ h $ metre high and b metre wide, the ball will hit the edge of the nth step, where $ n $ is

The motor of an engine is rotating about its axis with an angular velocity of 100 rev/m. If conies to rest in 15s, after being switched off. Assuming constant angular deceleration. What are the numbers of revolutions made by it before coming to rest?

By what percent the energy of a satellite has to be increased to shift it from an orbit of radius r to 3r?

A man slides down a light rope whose breaking strength is $ \eta $ times his weight. What should be his maximum acceleration so that the rope just not breaks?

A body moving with uniform acceleration describes 12 m in the third second of its motion and 20 m in the 5th second. Find the velocity after 10 th second.

The dimension of $ \frac{P}{a} $ in the equation $ p=\frac{b-{{t}^{2}}}{ax} $ where p is pressure, $ x $ is distance and t is time are

Two trains are moving towards each other with speeds of 20 m/s and 15 m/s relative to the ground. The first train sounds a whistle of frequency 600 Hz, the frequency of the whistle heard by a passenger in the second train before the train meeets is (the speed of sound in air is 340 m/s)

Power supplied to a particle of mass 2 kg varies with time as $ P=\frac{3{{t}^{2}}}{2}W. $ Here t is in second. If velocity of particle at $ t=0 $ is $ v=0, $ the velocity of particle at time $ t=2\,s $ will be

A pulley fixed to the ceiling carries a string with blocks of masses $m$ and $3m$ attached to its ends. The masses of string and pulley are negligible. When the system is released, the acceleration of centre of mass will be

To get an output $y = 1$ from the circuit shown in the figure, the input $A, B$ and $C$ must be respectively

A part of a long wire carrying a current i is bent into a circle of radius r as shown in figure. The net magnetic field at the centre O of the circular loop is

The molecule which has zero dipole moment is

Identify Z in the sequence $ C{{H}_{3}}COON{{H}_{4}}\xrightarrow{\Delta }X\xrightarrow[\Delta ]{{{P}_{2}}{{O}_{5}}}Y\xrightarrow{{{H}_{2}}O/{{H}^{+}}}Z $