List of top Questions asked in JCECE

The matrix [5103−2−46−1−2b]is a singular matrix, if b equals
A heavy brass sphere is hung from a weightless inelastic spring and as a simple pendulum its time period of oscillation is T. When the sphere is immersed in a non-viscous liquid of density 1/10 that of brass, it will act as a simple pendulum of period :
The .examples of diamagnetic, paramagnetic and ferromagnetic materials are respectively:
An $ \alpha - $ particle of mass m suffers one dimensional elastic collision with a nucleus of unknown mass. After the collision the $ \alpha - $ particle is scattered directly backwards losing 75% of its kinetic energy. The mass of the unknown nucleus is:
The resistors are connected as shown in the figure below. Find the equivalent resistance between the points A and B.
Law of multiple proportions is illustrated by one of the following pairs:
The number of isomeric hexanes is:
A block of mass 2 kg rests on a plane inclined at an angle of $ {{30}^{o}} $ with the horizontal. The coefficient of friction between the block and surface is 0.7. The frictional force acting on the block is:
Which of the following overlaps leads to bonding?
Wurtz's reaction involves'the reduction of alkyl halide with:
Which of the following statement is wrong?
$ Cis-trans $ isomers generally:
The two optical isomers given below, namely, :
The coagulating power of an electrolyte for arsenious sulphide decreases in the order:
Radioactive decay series of uranium is denoted as:
In one of the following reactions $ \text{HN}{{\text{O}}_{\text{3}}} $ does not behave as an oxidizing agent. Identify it:
Conversion of benzaldehyde to 3-phenyl-prop-2-en-1-oic acid is:
A person is standing in an elevator. In which situation he finds his weight less?
The radius of sphere is measured to be $ (2.1\,\pm \,0.5)\,cm. $ Calculate its surface area with error limits:
An object travels north with a velocity of $ 10\,m{{s}^{-1}} $ and then speeds up to a velocity of $ 25\,m{{s}^{-1}} $ in 5 s. The acceleration of the object in these 5 s is:
pH-scale was proposed by:
A child is swinging a swing. Minimum and maximum heights of swing from earths surface are 0.75 m and 2m respectively. The maximum velocity of this swing is:
A bicollateral vascular bundle has the following arrangement of tissues .................
Which of the following is not a protein?
Mohrs salt is