List of top Questions asked in JCECE- 2009

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

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:

The twinkling effect of star light is due to